CO24/7 Encyclopedia Code System

001 	without 1. Nf3, 1. c4, 1. d4, 1. e4
A00-A02: Rare & Irregular Openings 

002 	1. c4   without 1... c5, 1... e5, 1... Nf6
A10-A13: English Opening, Miscellaneous

003 	1. c4 c5   without 2. Nf3, 2. e4
A30, A34-A36: English Opening, Symmetrical Variation

004 	1. c4 c5 2. g3 g6 3. Bg2 Bg7 4. Nc3 Nc6 5. Nf3   without 5... Nd4, 5... Nf6
A37: English Opening, Symmetrical Variation - Main Line

005 	1. c4 e5   without 2. Nc3
A20: English Opening, Nimzowitsch Variation

006 	1. c4 e5 2. Nc3   without 2... Nc6, 2... Nf6
A21: English Opening, Kramnik-Shirov Counterattack & The Anglo-Dutch

007 	1. c4 e5 2. Nc3 Nc6
A25 & A27: English Opening, Closed Sicilian Reversed

008 	1. c4 e5 2. Nc3 Nc6 3. g3 g6 4. Bg2 Bg7 5. d3   without 5... f5
A25 & A26: English Opening, Closed Sicilian Reversed - Kingside Fianchettos

009 	1. c4 Nf6   without 2. Nf3, 2. d4
A15 & A16: English Opening, Anglo-Gruenfeld Defence

010 	1. c4 Nf6 2. Nc3   with 2... e6, 2... g6
A17-A19: English Opening, Flohr-Mikenas-Carls Variation

011 	1. c4 Nf6 2. Nc3 e5   without 3. Nf3
A22-A24: English Opening, Bremen System

012 	1. c4 Nf6 2. Nc3 e5 3. Nf3
A28: English Opening, Four Knights Variation

013 	1. c4 Nf6 2. Nc3 e5 3. Nf3 Nc6 4. e3
A28: English Opening, Romanishin & Stean Variations

014 	1. c4 Nf6 2. Nc3 e5 3. Nf3 Nc6 4. g3   without 4... d5, 4... Bb4
A29: English Opening, Four Knights Variation - Kingside Fianchetto

015 	1. c4 Nf6 2. Nc3 e5 3. Nf3 Nc6 4. g3 d5
A29: English Opening, Four Knights Variation - Kingside Fianchetto with 4... d5

016 	1. c4 Nf6 2. Nc3 e5 3. Nf3 Nc6 4. g3 d5 5. cxd5 Nxd5 6. Bg2 Nb6 7. O-O Be7 8. a3
A29: English Opening, Four Knights Variation - Kingside Fianchetto with 4... d5 (Main Line)

017 	1. c4 Nf6 2. Nc3 e5 3. Nf3 Nc6 4. g3 Bb4
A29: English Opening, Four Knights Variation - Kingside Fianchetto with 4... Bb4

018 	1. Nf3   without 1... d5, 1... Nf6
A04, A06 & B00: Reverse Gruenfeld; Lisitsin Gambit

019 	1. Nf3 c5 2. c4   without 2... Nf6
A31-A33: English Opening, Symmetrical Variation - Spielmann Defense & Geller Variation

020 	1. Nf3 c5 2. c4 Nc6 3. Nc3   without 3... Nf6
A27, A30 & A35: English Opening, Symmetrical Variation - Three Knights System

021 	1. Nf3 d5   without 2. d4, 2. g3
A06 & A09:  Reti Opening, Miscellaneous

022 	1. Nf3 d5 2. c4 c6   without 3. d4
A11: English Opening, Anglo-Slav

023 	1. Nf3 d5 2. g3   without 2... c6, 2... e6, 2... Nf6
A07 & A08: Reti Opening, King's Indian Attack with 2... c5

024 	1. Nf3 d5 2. g3 c6   without 3. c4, 3. d4
A07: Reti Opening, King's Indian Attack with 2... c6

025 	1. Nf3 Nf6   without 2. c4, 2. d4
A07 & A40: Reti Opening - King's Indian Attack with 2... g6; Polish Defense

026 	1. Nf3 Nf6 2. g3 d5   without 3. d4
A05:  Reti Opening - King's Indian Attack with 2... d5

027 	1. Nf3 Nf6 2. g3 d5 3. Bg2 c6   without 4. c4, 4. d4
A05:  Reti Opening - King's Indian Attack with 4... Bf5

028 	1. Nf3 Nf6 2. g3 d5 3. Bg2 c6 4. O-O Bg4
A05:  Reti Opening - King's Indian Attack with 4... Bg4

029 	1. Nf3 Nf6 2. c4   without 2... c5, 2... e6, 2... g6
A13, A14 & A17: English Opening, Agincourt Defense & Anglo-Indian Defense

030 	1. Nf3 Nf6 2. c4 c5   without 3. Nc3, 3. d4
A34: English Opening, Symmetrical (Rubinstein) & Asymmetrical Variations

031 	1. Nf3 Nf6 2. c4 c5 3. g3 b6   without 4. Nc3
A30: English Opening, Hedgehog Variation & The Double Fianchetto Defense

032 	1. Nf3 Nf6 2. c4 c5 3. Nc3   without 3... e6
A34, A38 & A39: English Opening, Asymmetrical & Four Knights Variations

033 	1. Nf3 Nf6 2. c4 c5 3. Nc3 e6   without 4. d4
A14 & D32: English Opening - Keres Defence; QGD Tarrasch - Symmetrical Variation

034 	1. Nf3 Nf6 2. c4 c5 3. Nc3 e6 4. d4   without 4... d5
A33: English Opening, Symmetrical Variation (Geller)

035 	1. Nf3 Nf6 2. c4 c5 3. Nc3 e6 4. d4 cxd4 5. Nxd4 Nc6 6. a3
A32: English Opening, Symmetrical Variation (Spielmann)

036 	1. Nf3 Nf6 2. c4 g6   without 3. d4
A24: English Opening, Two Knights Variation - Fianchetto Lines (Bremen System)

037 	1. Nf3 Nf6 2. c4 g6 3. Nc3 d5   without 4. d4
A15 & A16: English Opening, King's Knight Variation & The Anglo-Gruenfeld

038 	1. Nf3 Nf6 2. c4 g6 3. Nc3 d5 4. cxd5 Nxd5 5. g3
A16: English Opening, The Czech & Korchnoi's Variations

039 	1. Nf3 Nf6 2. c4 g6 3. Nc3 d5 4. cxd5 Nxd5   with 5. Qb3, 5. Qa4+
A16: English Opening, The Stein Attack

040 	1. Nf3 Nf6 2. c4 e6   without 3. Nc3, 3. d4
A13-A15: English Opening, Neo-Catalan Declined & The Romanishin Variation

041 	1. Nf3 Nf6 2. c4 e6 3. g3 d5 4. Bg2 dxc4
A13: English Opening, Neo-Catalan Accepted

042 	1. Nf3 Nf6 2. c4 e6 3. Nc3   without 3... c5
A17 & A18: English Opening, Nimzo-English (The Zvjaginsev-Krasenkow Attack) & Queen's Indian Formation

043 	1. Nf3 Nf6 2. c4 e6 3. Nc3 Bb4 4. Qc2
A17: English Opening, Nimzo-English with 4. Qc2

044 	1. Nf3 Nf6 2. c4 e6 3. Nc3 c5 4. g3 b6
A30: English Opening, Hedgehog Variation

045 	1. Nf3 Nf6 2. c4 e6 3. Nc3 c5 4. g3 b6 5. Bg2 Bb7 6. O-O Be7 7. d4
A30: English Opening, Hedgehog Variation with 7. d4

046 	1. d4   without 1... d6, 1... d5, 1... e6, 1... f5, 1... Nf6
A40, A41 & A43: Queen's Pawn Game (Colle System); Modern Defense - Pterodactyl Variation 

047 	1. d4 g6 2. c4 Bg7 3. Nc3   without 3... Nf6
A40 & A41: Modern Defense - Averbakh Variation

048 	1. d4 f5   without 2. g3
A80, A84 & A85: Dutch Defense, Normal Variation

049 	1. d4 f5 2. g3   without 2... e6
A81, A86 & A90: Dutch Defense, Fianchetto Variation (Stonewall & Classical)

050 	1. d4 f5 2. g3 Nf6 3. Bg2 g6
A87-A89: Dutch Defense, Leningrad Variation

051 	1. d4 d6   without 2. Nf3, 2. e4
A41 & A42: Tartakower System, Pillsbury Defense

052 	1. d4 d6 2. Nf3   without 2... Nf6
A41: Tartakower System, Wade Defense

053 	1. d4 e6   without 2. e4
A40: Keres Indian (Pseudo-Nimzo)

054 	1. d4 e6 2. c4 b6
A13: English Defense

055 	1. d4 d5   without 2. Nf3, 2. c4
D00: Queen's Pawn Game

056 	1. d4 d5 2. Nf3   without 2... Nf6
D02, D06 & D21: Queen's Pawn Game (Chigorin Variation, etc.)

057 	1. d4 d5 2. c4   without 2... dxc4, 2... c6, 2... e6
D06-D09: Queen's Gambit Declined, Chigorin Defense & Albin Countergambit

058 	1. d4 d5 2. c4 dxc4   without 3. e4
D20-D22: Queen's Gambit Accepted, Old & Alekhine Variations

059 	1. d4 d5 2. c4 dxc4 3. e4   without 3... e5
D20: Queen's Gambit Accepted, Rubinstein Variation, Alekhine System & Modern Defense

060 	1. d4 d5 2. c4 dxc4 3. e4 e5
D20: Queen's Gambit Accepted, McDonnell Defense

061 	1. d4 d5 2. c4 e6   without 3. Nf3
D31 & D32: Queen's Gambit Declined, Tarrasch Defense & Schara-Hennig

062 	1. d4 d5 2. c4 e6 3. Nc3 Be7 4. cxd5 exd5 5. Bf4 c6
D31: Queen's Gambit Declined, Alatortsev Variation

063 	1. d4 d5 2. c4 e6 3. Nf3   without 3... dxc4, 3... c6, 3... Nf6
D33 & D34:  Queen's Gambit Declined, Tarrasch Defense

064 	1. d4 d5 2. c4 c6   without 3. Nc3, 3. Nf3, 3. e3
D10: Slav Defense, Exchange Variation

065 	1. d4 d5 2. c4 c6 3. cxd5 cxd5 4. Nc3 Nf6 5. Nf3   without 5... a6, 5... e6, 5... g6
D14: Slav Defense, Exchange Variation - Trifunovic Variation & Symmetrical Line

066 	1. d4 d5 2. c4 c6 3. cxd5 cxd5 4. Nc3 Nf6 5. Nf3 a6
D10: Slav Defense, Exchange Variation with 5... a6

067 	1. d4 d5 2. c4 c6 3. Nc3   without 3... Nf6
A84, D10 & D31: Slav Stonewall & Semi-Slav

068 	1. d4 d5 2. c4 c6 3. Nc3 e6   with 4. Nf3, 4. e4
D31: Semi-Slav, Noteboom Variation & Marshall Gambit

069 	1. d4 d5 2. c4 c6 3. Nc3 Nf6   without 4. Nf3
D10 & D80: Slav Defence - Chebanenko Variation; Gruenfeld Defence - Schlechter Variation

070 	1. d4 d5 2. c4 c6 3. Nc3 Nf6 4. e3 a6 5. Qc2 e6
D10: Slav Defence - Chebanenko Variation with 5... e6

071 	1. d4 d5 2. c4 c6   with 3. e3, 3. Nf3
D10 & D11: Slav Defence, Sidelines

072 	1. d4 d5 2. c4 c6 3. Nf3 e6   with 4. e3, 4. Qc2
D11: Slav Defence, Modern Line

073 	1. d4 Nf6   without 2. Nf3, 2. c4
A45 & D01: Richter-Veresov Opening & Trompowsky Attack without 2... e6 & 2... Ne4

074 	1. d4 Nf6 2. Bg5 e6   without 3. Nf3
A45: Trompowsky Attack with 2... e6

075 	1. d4 Nf6 2. Bg5 Ne4
A45: Trompowsky Attack with 2... Ne4

076 	1. d4 Nf6 2. Nf3   without 2... d5, 2... e6, 2... g6
A43, A46 & A47: Old Benoni, Kingside Move Order

077 	1. d4 Nf6 2. Nf3 g6   without 3. Bg5, 3. c4, 3. g3
A48: Torre Attack, London System

078 	1. d4 Nf6 2. Nf3 g6 3. Bg5
A48: Torre Attack, Euwe Variation & Fianchetto Defense

079 	1. d4 Nf6 2. Nf3 g6 3. g3
A49: King's Indian Defence, Fianchetto without c4 (Przepiorka Variation)

080 	1. d4 d5 2. Nf3 Nf6
D02, D04, D23-D25: Colle System; Queen's Gambit Accepted (Mannheim & Showalter Variations)

081 	1. d4 d5 2. Nf3 Nf6 3. c4 dxc4 4. e3
D25 & D26: Queen's Gambit Accepted, Classical Defense (Steinitz & Development Variations)

082 	1. d4 d5 2. Nf3 Nf6 3. c4 dxc4 4. e3 e6 5. Bxc4 c5 6. O-O a6   without 7. a4, 7. Bb3, 7. dxc5
D27 & D28: Queen's Gambit Accepted, Rubinstein Variation (Alekhine System, Russian Gambit, etc.)

083 	1. d4 d5 2. Nf3 Nf6 3. c4 dxc4 4. e3 e6 5. Bxc4 c5 6. O-O a6 7. a4
D27: Queen's Gambit Accepted, Rubinstein Variation with 7. a4

084 	1. d4 d5 2. Nf3 Nf6 3. c4 dxc4 4. e3 e6 5. Bxc4 c5 6. O-O a6 7. dxc5
D27: Queen's Gambit Accepted, Rubinstein Variation with 7. dxc5 (Furman Variation)

085 	1. d4 d5 2. Nf3 Nf6 3. c4 dxc4 4. e3 e6 5. Bxc4 c5 6. O-O a6 7. Bb3
D27: Queen's Gambit Accepted, Rubinstein Variation with 7. Bb3

086 	1. d4 d5 2. c4 c6 3. Nf3 Nf6   without 4. Nc3, 4. e3
D11: Slav Defense, Breyer Variation & Bonet Gambit

087 	1. d4 d5 2. c4 c6 3. Nf3 Nf6 4. Qc2 dxc4 5. Qxc4 Bf5
D11: Slav Defense, Modern Line

088 	1. d4 d5 2. c4 c6 3. Nf3 Nf6 4. e3   without 4... a6, 4... e6, 4... Bf5, 4... Bg4
D11 & D80: Slav Defense, Quiet Variation; Gruenfeld Defense, Smyslov & Schlechter Variations

089 	1. d4 d5 2. c4 c6 3. Nf3 Nf6 4. e3 g6 5. Nc3 Bg7 6. Be2
D80:  Gruenfeld Defense, Schlechter Variation

090 	1. d4 d5 2. c4 c6 3. Nf3 Nf6 4. e3 a6   without 5. Nc3
D15: Slav Defense, Quiet Variation - Chebanenko Variation

091 	1. d4 d5 2. c4 c6 3. Nf3 Nf6 4. e3 Bg4
D12: Slav Defense, Pin Defense

092 	1. d4 d5 2. c4 c6 3. Nf3 Nf6 4. e3 Bg4 5. h3 Bxf3
D12: Slav Defense, Pin Defense with 5... Bxf3

093 	1. d4 d5 2. c4 c6 3. Nf3 Nf6 4. e3 e6   without 5. Nc3
D30: Semi-Slav, Pseudo-Meran & Quiet Variation (incl. Semmering Variation)

094 	1. d4 d5 2. c4 c6 3. Nf3 Nf6 4. e3 Bf5
D12: Slav Defense, Schallopp Defense (Amsterdam & Rotterdam Variations)

095 	1. d4 d5 2. c4 c6 3. Nf3 Nf6 4. e3 Bf5 5. Nc3 e6 6. Nh4   without 6... Bg6
D12: Slav Defense, Schallopp Defense without 6... Bg6

096 	1. d4 d5 2. c4 c6 3. Nf3 Nf6 4. e3 Bf5 5. Nc3 e6 6. Nh4 Bg6   without 7. Nxg6
D12: Slav Defense, Schallopp Defense without 7. Nxg6

097 	1. d4 d5 2. c4 c6 3. Nf3 Nf6 4. e3 Bf5 5. Nc3 e6 6. Nh4 Bg6 7. Nxg6
D12: Slav Defense, Schallopp Defense with 7. Nxg6

098 	1. d4 d5 2. c4 c6 3. Nf3 Nf6 4. Nc3   without 4... dxc4, 4... e6
D15: Slav Defense, Three Knights Variation (Suchting, Schlechter and Chebanenko Variations)

099 	1. d4 d5 2. c4 c6 3. Nf3 Nf6 4. Nc3 a6 5. a4
D15: Slav Defense, Chebanenko Variation with 5. a4

100 	1. d4 d5 2. c4 c6 3. Nf3 Nf6 4. Nc3 a6 5. c5   without 5... Nbd7
D15: Slav Defense, Chebanenko Variation with 5. c5

101 	1. d4 d5 2. c4 c6 3. Nf3 Nf6 4. Nc3 a6 5. c5 Nbd7
D15: Slav Defense, Chebanenko Variation with 5. c5 Nbd7

102 	1. d4 d5 2. c4 c6 3. Nf3 Nf6 4. Nc3 a6 5. e3   without 5... e6, 5... Bf5
D15: Slav Defense, Chebanenko Variation with 5. e3

103 	1. d4 d5 2. c4 c6 3. Nf3 Nf6 4. Nc3 a6 5. e3 b5 6. b3
D15: Slav Defense, Chebanenko Variation with 5. e3 b5 6. b3

104 	1. d4 d5 2. c4 c6 3. Nf3 Nf6 4. Nc3 dxc4
D15 & D16: Slav Defense, Two Knights Attack (Alekhine & Alapin Variations)

105 	1. d4 d5 2. c4 c6 3. Nf3 Nf6 4. Nc3 dxc4 5. a4 e6 6. e3
D16: Slav Defense, Alapin Variation - Soultanbeieff Variation with 6. e3

106 	1. d4 d5 2. c4 c6 3. Nf3 Nf6 4. Nc3 dxc4 5. a4 Bf5   without 6. Ne5
D17-D19: Open Slav Defense, Czech Defense without 6. Ne5

107 	1. d4 d5 2. c4 c6 3. Nf3 Nf6 4. Nc3 dxc4 5. a4 Bf5 6. e3 e6 7. Bxc4 Bb4 8. O-O Nbd7   without 9. Qe2
D18:  Open Slav Defense, Czech Defense - Dutch Variation without 9. Qe2

108 	1. d4 d5 2. c4 c6 3. Nf3 Nf6 4. Nc3 dxc4 5. a4 Bf5 6. e3 e6 7. Bxc4 Bb4 8. O-O Nbd7 9. Qe2
D18:  Open Slav Defense, Czech Defense - Dutch Variation with 9. Qe2

109 	1. d4 d5 2. c4 c6 3. Nf3 Nf6 4. Nc3 dxc4 5. a4 Bf5 6. Ne5   without 6... Nbd7
D17: Open Slav Defense, Krause Attack (Sharp Line - Wiesbaden Variation)

110 	1. d4 d5 2. c4 c6 3. Nf3 Nf6 4. Nc3 dxc4 5. a4 Bf5 6. Ne5 Nbd7
D17: Open Slav Defense, Krause Attack with 6... Nbd7

111 	1. d4 d5 2. c4 c6 3. Nf3 Nf6 4. Nc3 dxc4 5. a4 Bf5 6. Ne5 Nbd7 7. Nxc4 Qc7
D17: Open Slav Defense, Carlsbad Variation

112 	1. d4 Nf6 2. Nf3 e6   without 3. Bg5, 3. c4, 3. g3
A46 & D05: Queen's Pawn Game - Jussupow-Rubinstein & London Systems; Colle System (Classical Defense & Rubinstein Attack)

113 	1. d4 Nf6 2. Nf3 e6 3. Bg5
A46: Torre Attack, Nimzowitsch Variation & Petrosian Gambit

114 	1. d4 Nf6 2. Nf3 e6 3. g3
A46: Queen's Pawn Game, Knights Variation - Indian Game with 3. g3

115 	1. d4 Nf6 2. c4   without 2... c5, 2... d5, 2... e6, 2... g6
A50-A55: Budapest Gambit & Old Indian

116 	1. d4 Nf6 2. c4 c5   without 3. d5
A31 & A32: English Opening, Symmetrical Variation (Anti-Benoni Variation & Spielmann Defense)

117 	1. d4 Nf6 2. c4 c5 3. d5   without 3... b5
A56, A60-A61, A65-A67: Modern Benoni, Snake & Pawn Storm Variations

118 	1. d4 Nf6 2. c4 c5 3. d5 e6 4. Nc3 exd5 5. cxd5 d6 6. Nf3
A61: Modern Benoni, Uhlmann & Knight's Tour Variations

119 	1. d4 Nf6 2. c4 c5 3. d5 e6 4. Nc3 exd5 5. cxd5 d6 6. Nf3 g6 7. g3
A62: Modern Benoni, Fianchetto Variation (Hastings Defense)

120 	1. d4 Nf6 2. c4 c5 3. d5 e6 4. Nc3 exd5 5. cxd5 d6 6. Nf3 g6 7. e4
A61 & A70: Modern Benoni, Penrose & Classical Variations

121 	1. d4 Nf6 2. c4 c5 3. d5 b5
A57: Benko Gambit, Declined & Accepted

122 	1. d4 Nf6 2. c4 c5 3. d5 b5 4. cxb5 a6 5. bxa6
A58 & A59: Benko Gambit Accepted, Fianchetto & King Walk Variations

123 	1. d4 Nf6 2. c4 g6   without 3. Nc3, 3. Nf3
D70: Neo-Gruenfeld Defense

124 	1. d4 Nf6 2. c4 g6 3. g3 Bg7   without 4. Nc3, 4. Nf3
D71: Neo-Gruenfeld Defense, Exchange & Counterthrust Variations

125 	1. d4 Nf6 2. c4 g6 3. Nf3
E60: King's Indian Defense, King's Knight Variation

126 	1. d4 Nf6 2. c4 g6 3. Nf3 Bg7 4. g3 O-O   without 5. Nc3
A39: English Opening - Symmetrical Defense (Mecking Variation)

127 	1. d4 Nf6 2. c4 g6 3. Nf3 Bg7 4. g3 O-O 5. Bg2 d6
E60, E62, E64-E67: King's Indian Defense, Yugoslav Attack & Larsen, Kavalek & Benjamin Defenses

128 	1. d4 Nf6 2. c4 g6 3. Nf3 Bg7 4. g3 O-O 5. Bg2 d6 6. O-O Nc6
E62: King's Indian Defense, Carlsbad Variation

129 	1. d4 Nf6 2. c4 g6 3. Nf3 Bg7 4. g3 O-O 5. Bg2 d6 6. O-O Nc6 7. Nc3 a6
E63: King's Indian Defense, Carlsbad Variation - Panno Variation

130 	1. d4 Nf6 2. c4 g6 3. Nf3 Bg7 4. g3 O-O 5. Bg2 d6 6. O-O Nbd7
E67: King's Indian Defense, Debrecen Defense

131 	1. d4 Nf6 2. c4 g6 3. Nf3 Bg7 4. g3 c6
D78: Neo-Gruenfeld Defense, Original Defense

132 	1. d4 Nf6 2. c4 g6 3. Nf3 Bg7 4. g3 c6 5. Bg2 d5 6. cxd5
D78 & D79: Neo-Gruenfeld Defense, Delayed Exchange Variation

133 	1. d4 Nf6 2. c4 g6 3. Nf3 Bg7 4. g3 d5   without 5. Nc3, 5. cxd5
D77 & D78: Neo-Gruenfeld Defense, Classical Variation (Polgar Variation & Modern Defense)

134 	1. d4 Nf6 2. c4 g6 3. Nf3 Bg7 4. g3 d5 5. cxd5
D71: Neo-Gruenfeld Defense, Fianchetto/Exchange Variation

135 	1. d4 Nf6 2. c4 g6 3. Nf3 Bg7 4. g3 d5 5. cxd5 Nxd5 6. Bg2 Nb6 7. Nc3 Nc6 8. e3 O-O 9. O-O Re8
D71: Neo-Gruenfeld Defense, Fianchetto/Exchange Variation, Main Line

136 	1. d4 Nf6 2. c4 g6 3. Nc3   without 3... Bg7
D80, D81: Gruenfeld Defense, Accelerated Russian & Stockholm Variations

137 	1. d4 Nf6 2. c4 g6 3. Nc3 d5 4. Bg5 Ne4
D80: Gruenfeld Defense, Stockholm Variation with 4... Ne4

138 	1. d4 Nf6 2. c4 g6 3. Nc3 d5 4. Bf4
D82 & D83: Gruenfeld Defense, Brinckmann Attack

139 	1. d4 Nf6 2. c4 g6 3. Nc3 d5 4. cxd5
D85: Gruenfeld Defense, Exchange Variation

140 	1. d4 Nf6 2. c4 g6 3. Nc3 d5 4. cxd5 Nxd5 5. e4 Nxc3 6. bxc3 Bg7   without 7. Bc4, 7. Nf3
D85: Gruenfeld Defense, Exchange Variation (Sidelines)

141 	1. d4 Nf6 2. c4 g6 3. Nc3 d5 4. cxd5 Nxd5 5. e4 Nxc3 6. bxc3 Bg7 7. Nf3
D85: Gruenfeld Defense, Exchange Variation (Modern Main Line)

142 	1. d4 Nf6 2. c4 g6 3. Nc3 d5 4. cxd5 Nxd5 5. e4 Nxc3 6. bxc3 Bg7 7. Nf3 c5 8. Be3 Qa5 9. Qd2
D85: Gruenfeld Defense, Exchange Variation (Modern Main Line with 8. Be3)

143 	1. d4 Nf6 2. c4 g6 3. Nc3 d5 4. cxd5 Nxd5 5. e4 Nxc3 6. bxc3 Bg7 7. Nf3 c5 8. Rb1
D85: Gruenfeld Defense, Exchange Variation (Modern Main Line with 8. Rb1)

144 	1. d4 Nf6 2. c4 g6 3. Nc3 d5 4. cxd5 Nxd5 5. e4 Nxc3 6. bxc3 Bg7 7. Bc4
D86 & D87:  Gruenfeld Defense, Exchange Variation (Classical Main Line)

145 	1. d4 Nf6 2. c4 g6 3. Nc3 d5 4. cxd5 Nxd5 5. e4 Nxc3 6. bxc3 Bg7 7. Bc4 c5 8. Ne2 Nc6 9. Be3 O-O 10. O-O   with 10... Bg4, 10... Qc7
D87-89: Gruenfeld Defense, Exchange Variation (Classical Main Line incl. Sokolsky Variation)

146 	1. d4 Nf6 2. c4 g6 3. Nc3 d5 4. Nf3   without 4... c6
D90, D92-D94: Gruenfeld Defense, Three Knights Variation (incl. Hungarian Attack & Burille Variation)

147 	1. d4 Nf6 2. c4 g6 3. Nc3 d5 4. Nf3 Bg7 5. Bg5
D91: Gruenfeld Defense, Petrosian System

148 	1. d4 Nf6 2. c4 g6 3. Nc3 d5 4. Nf3 Bg7 5. Qb3
D96-D99: Gruenfeld Defense, Russian Variation

149 	1. d4 Nf6 2. c4 g6 3. Nc3 d5 4. Nf3 Bg7 5. Qb3 dxc4 6. Qxc4 O-O 7. e4 a6
D97: Gruenfeld Defense, Russian Variation (Hungarian Variation)

150 	1. d4 Nf6 2. c4 g6 3. Nc3 Bg7   without 4. e4
E61: King's Indian Defense, Sidelines & Smyslov Variation

151 	1. d4 Nf6 2. c4 g6 3. Nc3 Bg7 4. e4
A68-A69, E70, E72, E76-E79: King's Indian Defense - Normal Variation; Modern Benoni - Four Pawns Attack 

152 	1. d4 Nf6 2. c4 g6 3. Nc3 Bg7 4. e4 d6   with 5. h3, 5. Bd3
E71: King's Indian Defense, Makogonov Variation

153 	1. d4 Nf6 2. c4 g6 3. Nc3 Bg7 4. e4 d6 5. f3
E80 & E81: King's Indian Defense, Saemisch Variation (Steiner Attack & Normal Defense)

154 	1. d4 Nf6 2. c4 g6 3. Nc3 Bg7 4. e4 d6 5. f3 O-O 6. Be3   without 6... c5
E81-E89:  King's Indian Defense, Saemisch Variation - Normal Defense without 6... c5

155 	1. d4 Nf6 2. c4 g6 3. Nc3 Bg7 4. e4 d6 5. f3 O-O 6. Be3 c5
E81:  King's Indian Defense, Saemisch Variation - Normal Defense with 6... c5

156 	1. d4 Nf6 2. c4 g6 3. Nc3 Bg7 4. e4 d6 5. Be2
E73-E75: King's Indian Defense, Averbakh Variation & Semi-Averbakh System

157 	1. d4 Nf6 2. c4 g6 3. Nc3 Bg7 4. e4 d6 5. Nf3
E90 & E91: King's Indian Defense, Larsen Variation & Other Sidelines after 5. Nf3

158 	1. d4 Nf6 2. c4 g6 3. Nc3 Bg7 4. e4 d6 5. Nf3 O-O 6. Be2   without 6... e5
E91: King's Indian Defense, Orthodox Variation (incl. Kazakh Variation)

159 	1. d4 Nf6 2. c4 g6 3. Nc3 Bg7 4. e4 d6 5. Nf3 O-O 6. Be2 e5   without 7. Be3, 7. O-O
E92: King's Indian Defense, Petrosian Variation (incl. Stein Defense)

160 	1. d4 Nf6 2. c4 g6 3. Nc3 Bg7 4. e4 d6 5. Nf3 O-O 6. Be2 e5 7. Be3   without 7... Ng4, 7... Nbd7
E92: King's Indian Defense, Gligoric-Taimanov Variation without 7... Ng4 & 7... Nbd7

161 	1. d4 Nf6 2. c4 g6 3. Nc3 Bg7 4. e4 d6 5. Nf3 O-O 6. Be2 e5 7. Be3 Ng4
E92: King's Indian Defense, Gligoric-Taimanov Variation with 7... Ng4

162 	1. d4 Nf6 2. c4 g6 3. Nc3 Bg7 4. e4 d6 5. Nf3 O-O 6. Be2 e5 7. O-O   without 7... Nbd7, 7... Nc6, 7... Na6
E94: King's Indian Defense, Ukrainian Defense & Donner Variation

163 	1. d4 Nf6 2. c4 g6 3. Nc3 Bg7 4. e4 d6 5. Nf3 O-O 6. Be2 e5 7. O-O Nbd7
E91: King's Indian Defense, Orthodox Variation with 6... e5 7. O-O Nbd7

164 	1. d4 Nf6 2. c4 g6 3. Nc3 Bg7 4. e4 d6 5. Nf3 O-O 6. Be2 e5 7. O-O Na6   without 8. Be3
E94: King's Indian Defense, Glek Defense without 8. Be3

165 	1. d4 Nf6 2. c4 g6 3. Nc3 Bg7 4. e4 d6 5. Nf3 O-O 6. Be2 e5 7. O-O Na6 8. Be3
E94: King's Indian Defense, Glek Defense with 8. Be3

166 	1. d4 Nf6 2. c4 g6 3. Nc3 Bg7 4. e4 d6 5. Nf3 O-O 6. Be2 e5 7. O-O Nc6
E97: King's Indian Defense, Aronin-Taimanov/Mar del Plata Defense

167 	1. d4 Nf6 2. c4 g6 3. Nc3 Bg7 4. e4 d6 5. Nf3 O-O 6. Be2 e5 7. O-O Nc6 8. d5 Ne7 9. Ne1
E97: King's Indian Defense, Aronin-Taimanov/Mar del Plata Defense - Normal Variation

168 	1. d4 Nf6 2. c4 g6 3. Nc3 Bg7 4. e4 d6 5. Nf3 O-O 6. Be2 e5 7. O-O Nc6 8. d5 Ne7 9. b4   without 9... Nh5
E97: King's Indian Defense, Aronin-Taimanov/Mar del Plata Defense - Bayonet Attack without 9... Nh5

169 	1. d4 Nf6 2. c4 g6 3. Nc3 Bg7 4. e4 d6 5. Nf3 O-O 6. Be2 e5 7. O-O Nc6 8. d5 Ne7 9. b4 Nh5
E97: King's Indian Defense, Aronin-Taimanov/Mar del Plata Defense - Bayonet Attack with 9... Nh5

170 	1. d4 Nf6 2. c4 e6   without 3. Nc3, 3. Bg5, 3. Nf3
A60, E00 & E01: Modern Benoni (Early Fianchetto) & Catalan Opening

171 	1. d4 Nf6 2. c4 e6 3. Nc3   without 3... Bb4
D35, D36 & D50: Queen's Gambit Declined, Sidelines & Exchange Variation

172 	1. d4 Nf6 2. c4 e6 3. Nc3 d5 4. cxd5 exd5 5. Bg5 Be7   without 6. Nf3
D35: Queen's Gambit Declined, Positional Variation

173 	1. d4 Nf6 2. c4 e6 3. Nc3 Bb4   without 4. Qc2, 4. Nf3, 4. e3, 4. f3
E20, E22-E24 & E30: Nimzo-Indian Defense, Steiner, Speilmann, Saemisch & Leningrad Variations

174 	1. d4 Nf6 2. c4 e6 3. Nc3 Bb4 4. f3
E20 & E25: Nimzo-Indian Defense, Kmoch Variation (Keres & Romanovsky Variations)

175 	1. d4 Nf6 2. c4 e6 3. Nc3 Bb4 4. Qc2   without 4... c5, 4... O-O
E32-E34 & E37: Nimzo-Indian Defense, Classical Variation (Milner-Barry, Old Zuerich, Noa & San Remo Variations)  

176 	1. d4 Nf6 2. c4 e6 3. Nc3 Bb4 4. Qc2 d5 5. cxd5
E34: Nimzo-Indian Defense, Classical Variation - Noa Variation with 5. cxd5

177 	1. d4 Nf6 2. c4 e6 3. Nc3 Bb4 4. Qc2 d5 5. cxd5 Qxd5   with 6. e3, 6. Nf3
E35: Nimzo-Indian Defense, Classical Variation - Noa Variation (Romanishin Variation & Beliavsky Gambit)

178 	1. d4 Nf6 2. c4 e6 3. Nc3 Bb4 4. Qc2 c5
E38: Nimzo-Indian Defense, Classical Variation - Berlin Variation

179 	1. d4 Nf6 2. c4 e6 3. Nc3 Bb4 4. Qc2 c5 5. dxc5 O-O   without 6. Nf3
E39: Nimzo-Indian Defense, Classical Variation - Berlin Variation (Pirc Variation)

180 	1. d4 Nf6 2. c4 e6 3. Nc3 Bb4 4. Qc2 O-O   without 5. a3
E32: Nimzo-Indian Defense, Classical Variation with 4... O-O

181 	1. d4 Nf6 2. c4 e6 3. Nc3 Bb4 4. Qc2 O-O 5. a3
E32 & E33: Nimzo-Indian Defense, Classical Variation with 4... O-O 5. a3 (incl. Vitolinsh-Adorjan Gambit)

182 	1. d4 Nf6 2. c4 e6 3. Nc3 Bb4 4. Qc2 O-O 5. a3 Bxc3+ 6. Qxc3 d5
E32: Nimzo-Indian Defense, Classical Variation with 6... d5

183 	1. d4 Nf6 2. c4 e6 3. Nc3 Bb4 4. Qc2 O-O 5. a3 Bxc3+ 6. Qxc3 b6   without 7. Bg5
E32: Nimzo-Indian Defense, Classical Variation - Keres Defense without 7. Bg5

184 	1. d4 Nf6 2. c4 e6 3. Nc3 Bb4 4. Qc2 O-O 5. a3 Bxc3+ 6. Qxc3 b6 7. Bg5
E32: Nimzo-Indian Defense, Classical Variation - Keres Defense with 7. Bg5

185 	1. d4 Nf6 2. c4 e6 3. Nc3 Bb4 4. Qc2 O-O 5. a3 Bxc3+ 6. Qxc3 b6 7. Bg5 Bb7 8. e3
E32: Nimzo-Indian Defense, Classical Variation - Keres Defense with 7. Bg5 Bb7 8. e3

186 	1. d4 Nf6 2. c4 e6 3. Nc3 Bb4 4. e3   without 4... c5, 4... O-O
E40 & E43: Nimzo-Indian Defense, Rubinstein Variation (incl. Taimanov, Keres & St. Petersburg Variations)

187 	1. d4 Nf6 2. c4 e6 3. Nc3 Bb4 4. e3 c5   without 5. Nge2
E41: Nimzo-Indian Defense, Rubinstein Variation - Huebner Variation

188 	1. d4 Nf6 2. c4 e6 3. Nc3 Bb4 4. e3 c5 5. Nge2
E41: Nimzo-Indian Defense, Rubinstein Variation - Huebner Variation with 5. Nge2

189 	1. d4 Nf6 2. c4 e6 3. Nc3 Bb4 4. e3 O-O   without 5. Bd3
E46, E50 & E51: Nimzo-Indian Defense, Rubinstein Variation - Normal Variation without 5. Bd3

190 	1. d4 Nf6 2. c4 e6 3. Nc3 Bb4 4. e3 O-O 5. Bd3
E47-E49: Nimzo-Indian Defense, Rubinstein Variation - Normal Variation with 5. Bd3

191 	1. d4 Nf6 2. c4 e6 3. Nc3 Bb4 4. e3 O-O 5. Bd3 d5 6. Nf3
E48, E52 & E53: Nimzo-Indian Defense, Rubinstein Variation - Normal Variation (incl. Schlechter & Bernstein Defenses)

192 	1. d4 Nf6 2. c4 e6 3. Nc3 Bb4 4. e3 O-O 5. Bd3 d5 6. Nf3 c5 7. O-O dxc4 8. Bxc4 Nbd7
E48 & E55: Nimzo-Indian Defense, Rubinstein Variation - Normal Variation (Bronstein Variation)

193 	1. d4 Nf6 2. c4 e6 3. Nc3 Bb4 4. e3 O-O 5. Bd3 d5 6. Nf3 c5 7. O-O dxc4 8. Bxc4 cxd4
E53: Nimzo-Indian Defense, Rubinstein Variation - Normal Variation (Bernstein Defense - Gligoric System)

194 	1. d4 Nf6 2. c4 e6 3. Nc3 Bb4 4. e3 O-O 5. Bd3 d5 6. Nf3 c5 7. O-O Nc6
E56: Nimzo-Indian Defense, Rubinstein Variation - Normal Variation (Bernstein Variation)

195 	1. d4 Nf6 2. c4 e6 3. Nf3   without 3... b6, 3... d5, 3... Bb4+
E10: Blumenfeld Countergambit & Dzindzi-Indian Defense

196 	1. d4 Nf6 2. c4 e6 3. Nf3 Bb4+   without 4. Nc3, 4. Bd2
E11: Bogo-Indian Defense (incl. Gruenfeld Variation)

197 	1. d4 Nf6 2. c4 e6 3. Nf3 Bb4+ 4. Nbd2 b6
E11: Bogo-Indian Defense, Gruenfeld Variation with 4... b6

198 	1. d4 Nf6 2. c4 e6 3. Nf3 Bb4+ 4. Nc3   without 4... b6, 4... d5
E20 & E21: Nimzo-Indian Defense, Three Knights Variation (incl. Romanishin Variation)

199 	1. d4 Nf6 2. c4 e6 3. Nf3 Bb4+ 4. Nc3 c5 5. g3 cxd4 6. Nxd4   without 6... Nc6, 6... Qc7
E20: Nimzo-Indian Defense, English Hybrid

200 	1. d4 Nf6 2. c4 e6 3. Nf3 Bb4+ 4. Bd2   without 4... a5, 4... Qe7
E11: Bogo-Indian Defense with 4. Bd2

201 	1. d4 Nf6 2. c4 e6 3. Nf3 Bb4+ 4. Bd2   with 4... a5, 4... Qe7
E11: Bogo-Indian Defense with 4. Bd2 (incl. Nimzowitsch Variation)

202 	1. d4 Nf6 2. c4 e6 3. Nf3 b6   without 4. Nc3, 4. a3, 4. g3
E12 & E14: Queen's Indian Defense, Miles & Spassky Variations

203 	1. d4 Nf6 2. c4 e6 3. Nf3 b6 4. Nc3   without 4... Bb4
E12: Queen's Indian Defense, Kasparov Variation (incl. Botvinnik Variation)

204 	1. d4 Nf6 2. c4 e6 3. Nf3 b6 4. Nc3 Bb4   without 5. Bg5
E12: Queen's Indian Defense, Kasparov Variation with 4... Bb4

205 	1. d4 Nf6 2. c4 e6 3. Nf3 b6 4. Nc3 Bb4 5. Bg5
E12: Queen's Indian Defense, Kasparov Variation with 4... Bb4 5. Bg5

206 	1. d4 Nf6 2. c4 e6 3. Nf3 b6 4. a3   without 4... Bb7
E12: Queen's Indian Defense, Petrosian Variation without 4... Bb7

207 	1. d4 Nf6 2. c4 e6 3. Nf3 b6 4. a3 Ba6 5. Qc2
E12: Queen's Indian Defense, Petrosian Variation - Farago Defense

208 	1. d4 Nf6 2. c4 e6 3. Nf3 b6 4. a3 Bb7
E12: Queen's Indian Defense, Kasparov-Petrosian Variation (incl. Hedgehog Variation)

209 	1. d4 Nf6 2. c4 e6 3. Nf3 b6 4. a3 Bb7 5. Nc3 d5 6. Bg5
E12: Queen's Indian Defense, Kasparov-Petrosian Variation with 5... d5 6. Bg5

210 	1. d4 Nf6 2. c4 e6 3. Nf3 b6 4. a3 Bb7 5. Nc3 d5 6. cxd5
E12: Queen's Indian Defense, Kasparov-Petrosian Variation with 5... d5 6. cxd5

211 	1. d4 Nf6 2. c4 e6 3. Nf3 b6 4. a3 Bb7 5. Nc3 d5 6. cxd5 Nxd5 7. e3
E12: Queen's Indian Defense, Kasparov-Petrosian Variation with 5... d5 6. cxd5 Nxd5 7. e3

212 	1. d4 Nf6 2. c4 e6 3. Nf3 b6 4. a3 Bb7 5. Nc3 d5 6. cxd5 Nxd5 7. Qc2   without 7... c5
E12: Queen's Indian Defense, Kasparov-Petrosian Variation (incl. Murey Variation)

213 	1. d4 Nf6 2. c4 e6 3. Nf3 b6 4. g3   without 4... Bb7, 4... Ba6
E15 & E16: Queen's Indian Defense, Fianchetto System (incl. Riumin & Yates Variations)

214 	1. d4 Nf6 2. c4 e6 3. Nf3 b6 4. g3 Bb7   without 5. Nc3
E15-E17: Queen's Indian Defense, Fianchetto Traditional

215 	1. d4 Nf6 2. c4 e6 3. Nf3 b6 4. g3 Bb7 5. Bg2 Be7 6. Nc3 Ne4 7. Bd2
E17: Queen's Indian Defense, Opocensky Variation

216 	1. d4 Nf6 2. c4 e6 3. Nf3 b6 4. g3 Bb7 5. Bg2 Be7 6. O-O
E17: Queen's Indian Defense, Classical Variation (Euwe & Kramnik Variations, Taimanov & Polugaevsky Gambits)

217 	1. d4 Nf6 2. c4 e6 3. Nf3 b6 4. g3 Bb7 5. Bg2 Be7 6. O-O O-O 7. Nc3
E17 & E18: Queen's Indian Defense, Classical Variation (incl. Tiviakov Defense)

218 	1. d4 Nf6 2. c4 e6 3. Nf3 b6 4. g3 Bb7 5. Bg2 Be7 6. O-O O-O 7. Nc3 Ne4 8. Bd2
E17: Queen's Indian Defense, Classical Variation with 7... Ne4 8. Bd2

219 	1. d4 Nf6 2. c4 e6 3. Nf3 b6 4. g3 Ba6   without 5. Nbd2, 5. Qc2, 5.Qa4, 5. b3
E15: Queen's Indian Defense, Nimzowitsch Variation (incl. Timman's Line)

220 	1. d4 Nf6 2. c4 e6 3. Nf3 b6 4. g3 Ba6 5. Qc2
E15: Queen's Indian Defense, Nimzowitsch Variation with 5. Qc2

221 	1. d4 Nf6 2. c4 e6 3. Nf3 b6 4. g3 Ba6 5. Qa4
E15: Queen's Indian Defense, Nimzowitsch Variation (Nimzowitsch Attack)

222 	1. d4 Nf6 2. c4 e6 3. Nf3 b6 4. g3 Ba6 5. Nbd2
E15: Queen's Indian Defense, Nimzowitsch Variation with 5. Nbd2

223 	1. d4 Nf6 2. c4 e6 3. Nf3 b6 4. g3 Ba6 5. b3   without 5... Bb7, 5... Bb4+
E15: Queen's Indian Defense, Quiet Line

224 	1. d4 Nf6 2. c4 e6 3. Nf3 b6 4. g3 Ba6 5. b3 Bb7
E15: Queen's Indian Defense, Quiet Line with 5... Bb7

225 	1. d4 Nf6 2. c4 e6 3. Nf3 b6 4. g3 Ba6 5. b3 Bb4+
E15: Queen's Indian Defense, Quiet Line with 5... Bb4+

226 	1.  d4 Nf6 2. c4 e6 3. Nf3 b6 4. g3 Ba6 5. b3 Bb4+ 6. Bd2 Be7 7. Bg2   without 7... c6
E15: Queen's Indian Defense, Quiet Line with 5...  Bb4+ 6. Bd2 Be7 7. Bg2

227 	1. d4 Nf6 2. c4 e6 3. Nf3 b6 4. g3 Ba6 5. b3 Bb4+ 6. Bd2 Be7 7. Bg2 c6
E15: Queen's Indian Defense, Quiet Line with 5...  Bb4+ 6. Bd2 Be7 7. Bg2 c6

228 	1. d4 Nf6 2. c4 e6 3. Nf3 b6 4. g3 Ba6 5. b3 Bb4+ 6. Bd2 Be7 7. Bg2 c6 8. Bc3 d5 9. Ne5 Nfd7
E15: Queen's Indian Defense, Quiet Line with 5...  Bb4+ 6. Bd2 Be7 7. Bg2 c6 8. Bc3 d5 9. Ne5 Nfd7

229 	1. d4 Nf6 2. c4 e6 3. Nf3 d5   without 4. g3
D30 & D37: Queen's Gambit Declined, Traditional Variation (incl. Duras, Vienna & Capablanca Variations)

230 	1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. g3   without 4... dxc4, 4... Be7
E06 & E11: Catalan Defense, Closed Variation; Bogo-Indian/Catalan Hybrid

231 	1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. g3 Bb4+ 5. Bd2 Be7
E11: Bogo-Indian/Catalan Hybrid with 5. Bd2 Be7

232 	1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. g3 Bb4+ 5. Bd2 Be7 6. Bg2 O-O 7. O-O c6 8. Bf4
E08: Catalan Defense, Closed Variation - Main Line with 8. Bf4

233 	1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. g3 Bb4+ 5. Bd2 Be7 6. Bg2 O-O 7. O-O c6 8. Bf4 Nbd7 9. Qc2
E08: Catalan Defense, Closed Variation - Main Line with 8. Bf4 Nbd7 9. Qc2

234 	1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. g3 Bb4+ 5. Bd2 Be7 6. Bg2 O-O 7. O-O c6 8. Bf4 Nbd7 9. Qc2 b6 10. Rd1 Ba6   without 11. Nbd2
E08: Catalan Defense, Closed Variation - Main Line with 8. Bf4 Nbd7 9. Qc2 b6 10. Rd1 Ba6

235 	1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. g3 Be7
E06: Catalan Defense, Closed Variation with 4... Be7

236 	1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. g3 Be7 5. Bg2 O-O 6. O-O dxc4 7. Qc2 a6 8. a4
E06: Catalan Defense, Closed Variation with 4... Be7 5. Bg2 O-O 6. O-O dxc4 7. Qc2 a6 8. a4

237 	1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. g3 Be7 5. Bg2 O-O 6. O-O dxc4 7. Qc2 a6 8. Qxc4
E06: Catalan Defense, Closed Variation with 4... Be7 5. Bg2 O-O 6. O-O dxc4 7. Qc2 a6 8. Qxc4

238 	1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. g3 Be7 5. Bg2 O-O 6. O-O dxc4 7. Qc2 a6 8. Qxc4 b5 9. Qc2 Bb7 10. Bd2 Be4
E06: Catalan Defense, Closed Variation with 4... Be7 5. Bg2 O-O 6. O-O dxc4 7. Qc2 a6 8. Qxc4 b5 9. Qc2 Bb7 10. Bd2 Be4

239 	1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. g3 dxc4
E04 & E05: Catalan Defense, Open Defense (incl. Classical Line)

240 	1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. g3 dxc4 5. Bg2 Bb4+   without 6. Nc3
E04: Catalan Defense, Open Defense with 5... Bb4+

241 	1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. g3 dxc4 5. Bg2 Nc6
E05: Catalan Defense, Open Defense - Modern Sharp Variation

242 	1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. g3 dxc4 5. Bg2 a6
E04: Catalan Defense, Open Defense with 5... a6

243 	1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. Nc3 c5   without 5. e3
D40 & D41: Queen's Gambit Declined, Semi-Tarrasch (incl. Pillsbury & San Sebastian Variations)

244 	1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. Nc3 Nbd7
D35 & D51: Queen's Gambit Declined with 4... Nbd7 (incl. Saemisch Variation & Alekhine Gambit)

245 	1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. Nc3 dxc4   without 5. e4
D44: Semi-Slav, Vienna Variation

246 	1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. Nc3 dxc4 5. e4
D44: Semi-Slav, Vienna Variation with 5. e4

247 	1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. Nc3 dxc4 5. e4 Bb4 6. Bg5 c5 7. Bxc4
D44: Semi-Slav, Vienna Variation with 5. e4 Bb4 6. Bg5 c5 7. Bxc4

248 	1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. Nc3 Bb4   without 5. Bg5, 5. Qc2, 5. e3, 5. g3, 5. cxd5
D38: Queen's Gambit Declined, Ragozin Variation (incl. Alekhine Variation)

249 	1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. Nc3 Bb4 5. Bg5   without 5... O-O
D38, D39 & D51: Queen's Gambit Declined, Ragozin Variation; Vienna & Westphalian Variations

250 	1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. Nc3 Bb4 5. cxd5
D38: Queen's Gambit Declined, Ragozin Variation with 5. cxd5

251 	1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. Nc3 Bb4 5. cxd5 exd5 6. Bg5 Nbd7   without 7. e3
D38: Queen's Gambit Declined, Ragozin Variation with 5. cxd5 exd5 6. Bg5 Nbd7

252 	1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. Nc3 Bb4 5. cxd5 exd5 6. Bg5 Nbd7 7. e3
D38: Queen's Gambit Declined, Ragozin Variation with 5. cxd5 exd5 6. Bg5 Nbd7 7. e3

253 	1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. Nc3 Be7   without 5. Bg5
D37: Queen's Gambit Declined, Harrwitz Attack

254 	1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. Nc3 Be7 5. Bf4 O-O 6. e3 Nbd7   without 7. c5
D37: Queen's Gambit Declined, Harrwitz Attack - Main Line with 6... Nbd7

255 	1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. Nc3 Be7 5. Bf4 O-O 6. e3 Nbd7 7. c5
D37: Queen's Gambit Declined, Harrwitz Attack - Main Line with 7. c5

256 	1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. Nc3 Be7 5. Bf4 O-O 6. e3 c5
D37: Queen's Gambit Declined, Harrwitz Attack - Main Line with 6... c5

257 	1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. Nc3 Be7 5. Bf4 O-O 6. e3 c5 7. dxc5 Bxc5 8. a3
D37: Queen's Gambit Declined, Harrwitz Attack - Main Line with 8. a3

258 	1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. Nc3 Be7 5. Bg5   without 5... c6, 5... h6
D55, D60 & D63: Queen's Gambit Declined, Orthodox Variation (incl. Botvinnik & Rauser Variations)

259 	1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. Nc3 Be7 5. Bg5 h6   without 6. Bh4
D55: Queen's Gambit Declined, Petrosian Variation

260 	1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. Nc3 Be7 5. Bg5 h6 6. Bh4
D56 & D57: Queen's Gambit Declined, Lasker Variation (incl. Teichmann & Bernstein Variations)

261 	1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. Nc3 Be7 5. Bg5 h6 6. Bh4 O-O 7. e3 Ne4 8. Bxe7 Qxe7 9. Rc1
D56: Queen's Gambit Declined, Lasker Variation with 9. Rc1

262 	1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. Nc3 Be7 5. Bg5 h6 6. Bh4 O-O 7. e3 b6   without 8. Be2, 8. Bd3
D58 & D59: Queen's Gambit Declined, Tartakower Variation

263 	1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. Nc3 Be7 5. Bg5 h6 6. Bh4 O-O 7. e3 b6 8. Be2
D58: Queen's Gambit Declined, Tartakower Variation with 8. Be2

264 	1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. Nc3 Be7 5. Bg5 h6 6. Bh4 O-O 7. e3 b6 8. Bd3
D58: Queen's Gambit Declined, Tartakower Variation with 8. Bd3

265 	1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. Nc3 c6   without 5. Bg5, 5. e3
D35, D36 & E07: Queen's Gambit Declined - Exchange Variation; Catalan Opening - Botvinnik Variation

266 	1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. Nc3 c6 5. Bg5   without 5... h6, 5... Nbd7
D43 & D44: Queen's Gambit Declined - Anti-Meran Gambit; Semi-Slav Defense Accepted - Botvinnik Variation

267 	1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. Nc3 c6 5. Bg5 Nbd7   without 6. e3
D35 & D51: Queen's Gambit Declined, incl. Exchange Variation & Alekhine Variation

268 	1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. Nc3 c6 5. Bg5 Nbd7 6. cxd5 exd5 7. e3 Be7 8. Bd3
D35: Queen's Gambit Declined, Exchange Variation with 8. Bd3

269 	1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. Nc3 c6 5. Bg5 Nbd7 6. e3   without 6... Be7
D52: Queen's Gambit Declined, Cambridge Springs - Pillsbury Variation (incl. Bogoljubow Variation)

270 	1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. Nc3 c6 5. Bg5 h6   without 6. Bxf6
D44: Queen's Gambit Declined, Anti-Moscow Gambit

271 	1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. Nc3 c6 5. Bg5 h6 6. Bh4 dxc4 7. e4 g5 8. Bg3 b5 9. Be2 Bb7   with 10. O-O, 10. h4
D44: Queen's Gambit Declined, Anti-Moscow Gambit - Main Line

272 	1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. Nc3 c6 5. Bg5 h6 6. Bxf6
D30 & D43: Queen's Gambit Declined, Hastings Variation; Semi-Slav Defense with 6. Bxf6

273 	1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. Nc3 c6 5. Bg5 h6 6. Bxf6 Qxf6 7. e3 Nd7 8. Bd3
D43: Queen's Gambit Declined, Semi-Slav Defense with 6. Bxf6 - Main Line

274 	1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. Nc3 c6 5. e3   without 5... Nbd7
D45: Queen's Gambit Declined, Accelerated Meran

275 	1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. Nc3 c6 5. e3 Nbd7   without 6. Qc2
D45-D47: Queen's Gambit Declined, Semi-Slav Defense - Normal Variation without 6. Qc2

276 	1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. Nc3 c6 5. e3 Nbd7 6. Bd3 dxc4 7. Bxc4 b5 8. Bd3   without 8... a6, 8... Bb7
D47: Queen's Gambit Declined, Semi-Slav Defense - Neo-Meran (incl. Lundin Variation)

277 	1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. Nc3 c6 5. e3 Nbd7 6. Bd3 dxc4 7. Bxc4 b5 8. Bd3 a6
D48 & D49: Queen's Gambit Declined, Semi-Slav Defense - Neo-Meran (Reynolds Variation)

278 	1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. Nc3 c6 5. e3 Nbd7 6. Bd3 dxc4 7. Bxc4 b5 8. Bd3 Bb7   without 9. O-O
D47: Queen's Gambit Declined, Semi-Slav Defense - Neo-Meran (Wade Variation incl. Larsen Variation)

279 	1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. Nc3 c6 5. e3 Nbd7 6. Bd3 dxc4 7. Bxc4 b5 8. Bd3 Bb7 9. O-O
D47: Queen's Gambit Declined, Semi-Slav Defense - Neo-Meran (Wade Variation with 9. O-O)

280 	1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. Nc3 c6 5. e3 Nbd7 6. Qc2
D45: Queen's Gambit Declined, Semi-Slav Defense - Stoltz Variation (incl. Center Variation & Mikhalchishin Line)

281 	1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. Nc3 c6 5. e3 Nbd7 6. Qc2 Bd6 7. g4
D45: Queen's Gambit Declined, Semi-Slav Defense - Stoltz Variation (Shabalov Attack)

282 	1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. Nc3 c6 5. e3 Nbd7 6. Qc2 Bd6 7. b3
D45: Queen's Gambit Declined, Semi-Slav Defense - Stoltz Variation with 6... Bd6 7. b3

283 	1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. Nc3 c6 5. e3 Nbd7 6. Qc2 Bd6 7. Bd3
D45: Queen's Gambit Declined, Semi-Slav Defense - Stoltz Variation with 6... Bd6 7. Bd3

284 	1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. Nc3 c6 5. e3 Nbd7 6. Qc2 Bd6 7. Bd3 O-O 8. O-O dxc4 9. Bxc4 a6
D45: Queen's Gambit Declined, Semi-Slav Defense - Stoltz Variation (Main Line with 9... a6)

285 	1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. Nc3 c6 5. e3 Nbd7 6. Qc2 Bd6 7. Bd3 O-O 8. O-O dxc4 9. Bxc4 b5
D45: Queen's Gambit Declined, Semi-Slav Defense - Stoltz Variation (Main Line with 9... b5)

286 	1. e4   without 1... c6, 1... c5, 1... d6, 1... d5, 1... e6, 1... e5, 1... g6
B00, B02 & B03: Nimzowitsch, St. George & Basman Defenses; Alekhine Defense without 4. Nf3

287 	1. e4 Nf6 2. e5 Nd5 3. d4 d6 4. Nf3
B04 & B05: Alekhine Defense with 4. Nf3 (incl. Keres, Alburt, Larsen, Schmid & Flohr Variations)

288 	1. e4 d5
B01: Scandinavian Defense without 2. Nc3

289 	1. e4 d5 2. exd5 Qxd5 3. Nc3 Qd6
B01: Scandinavian Defense with 3... Qd6 (incl. Schiller-Pytel & Bronstein Variations)

290 	1. e4 g6
B06: Modern Defense, Bishop & Three Pawns Attack (incl. Gurgenidze Defense)

291 	1. e4 g6 2. d4 Bg7 3. Nf3
A40 & B06: Modern Defense, incl. Rossolimo Variation & Geller's System

292 	1. e4 d6
B06 & B07: Modern & Pirc Defense, Miscellaneous

293 	1. e4 d6 2. d4 g6 3. Nc3 Bg7 4. Be3
B06: Modern Defense with 4. Be3, incl. Pseudo-Austrian Attack

294 	1. e4 d6 2. d4 Nf6
B07: Czech Pirc Defense, Anti-Philidor & Lion's Jaw

295 	1. e4 d6 2. d4 Nf6 3. Nc3 e5
C41: Philidor Defense, Shirov Gambit

296 	1. e4 d6 2. d4 Nf6 3. Nc3 e5 4. Nf3 Nbd7 5. Bc4 Be7 6. O-O O-O
C41: Philidor Defense, Improved Hanham variation (incl. Larobok Variation)

297 	1. e4 d6 2. d4 Nf6 3. Nc3 g6   without 4. Be3, 4. Bf4, 4. Nf3, 4. f4
B07: Pirc Defense, Classical & Kholmov Systems and Byrne Variation

298 	1. e4 d6 2. d4 Nf6 3. Nc3 g6 4. Be3
B07: Pirc Defense with 4. Be3, incl. Sveshnikov-Jansa & 150 Attack

299 	1. e4 d6 2. d4 Nf6 3. Nc3 g6 4. f4
B09: Pirc Defense, Austrian Attack

300 	1. e4 d6 2. d4 Nf6 3. Nc3 g6 4. Nf3
B08: Pirc Defense, Two Knights System

301 	1. e4 c6   without 2. c4, 2. d4
B10 & B11: Caro-Kann Defense, Breyer Variation & Two Knights Attack

302 	1. e4 c6 2. c4
B10: Caro-Kann Defense, Accelerated Panov

303 	1. e4 c6 2. d4
B12 & B13: Caro-Kann Defense, incl. Maroczy & Exchange Variations

304 	1. e4 c6 2. d4 d5 3. exd5 cxd5 4. c4
B13 & B14: Caro-Kann Defense, Panov-Botvinnik Attack (incl. Carlsbad, Czerniak & Reifir-Spielmann Lines)

305 	1. e4 c6 2. d4 d5 3. exd5 cxd5 4. c4 Nf6 5. Nc3 e6
B14 & E41: Caro-Kann Defense - Panov-Botvinnik Attack; Nimzo-Indian Defense

306 	1. e4 c6 2. d4 d5 3. exd5 cxd5 4. c4 Nf6 5. Nc3 e6 6. Nf3 Bb4 7. cxd5 Nxd5 8. Qc2
B14: Caro-Kann Defense, Panov-Botvinnik Attack - Main Line with 8. Qc2

307 	1. e4 c6 2. d4 d5 3. Nc3
B15-B17: Caro-Kann Defense, incl. Gurgenidze System and Forgacs, Bronstein-Larsen & Karpov Variations

308 	1. e4 c6 2. d4 d5 3. Nc3 dxe4 4. Nxe4 Nd7 5. Bc4
B17: Caro-Kann Defense, Karpov Variation (Tiviakov-Fischer Attack & Smyslov Variation)

309 	1. e4 c6 2. d4 d5 3. Nc3 dxe4 4. Nxe4 Nd7 5. Ng5
B17: Caro-Kann Defense, Karpov Variation with 5. Ng5 (incl. Ivanchuk Defense)

310 	1. e4 c6 2. d4 d5 3. Nc3 dxe4 4. Nxe4 Bf5
B18: Caro-Kann Defense, Classical Variation (incl. Flohr Variation)

311 	1. e4 c6 2. d4 d5 3. Nc3 dxe4 4. Nxe4 Bf5 5. Ng3 Bg6 6. h4
B18-B19:  Caro-Kann Defense, Classical Variation with 6. h4

312 	1. e4 c6 2. d4 d5 3. Nc3 dxe4 4. Nxe4 Bf5 5. Ng3 Bg6 6. h4 h6 7. Nf3 Nd7
B18 & B19: Caro-Kann Defense, Classical Variation - Main Line (incl. Seirawan Variation)

313 	1. e4 c6 2. d4 d5 3. Nc3 dxe4 4. Nxe4 Bf5 5. Ng3 Bg6 6. h4 h6 7. Nf3 Nd7 8. h5 Bh7 9. Bd3 Bxd3 10. Qxd3 e6 without 11. Bf4
B19: Caro-Kann Defense, Classical Variation - Main Line (Seirawan Variation without 11. Bf4)

314 	1. e4 c6 2. d4 d5 3. Nc3 dxe4 4. Nxe4 Bf5 5. Ng3 Bg6 6. h4 h6 7. Nf3 Nd7 8. h5 Bh7 9. Bd3 Bxd3 10. Qxd3 e6 11. Bf4
B19: Caro-Kann Defense, Classical Variation - Main Line (Seirawan Variation with 11. Bf4)

315 	1. e4 c6 2. d4 d5 3. e5
B12: Caro-Kann Defense, Advance Variation (incl. Botvinnik-Carls Defense and Bronstein & Bayonet Variations)

316 	1. e4 c6 2. d4 d5 3. e5 Bf5   with 4. Nd2, 4. h4
B12: Caro-Kann Defense, Advance Variation (incl. Tal Variation)

317 	1. e4 c6 2. d4 d5 3. e5 Bf5 4. Nc3
B12: Caro-Kann Defense, Advance Variation - Van der Wiel Attack

318 	1. e4 c6 2. d4 d5 3. e5 Bf5 4. Nf3
B12: Caro-Kann Defense, Advance Variation - Short Variation

319 	1. e4 c6 2. d4 d5 3. e5 Bf5 4. Nf3 e6 5. Be2 Ne7
B12: Caro-Kann Defense, Advance Variation - Short Variation with 5... Ne7

320 	1. e4 c6 2. d4 d5 3. e5 Bf5 4. Nf3 e6 5. Be2 c5
B12: Caro-Kann Defense, Advance Variation - Short Variation with 5... c5

321 	1. e4 e6   without 2. c4, 2. d4
C00: French Defense, King's Indian Attack

322 	1. e4 e6 2. d4
B00 & C01: Owen's Defense; French Defense - Exchange Variation

323 	1. e4 e6 2. d4 d5 3. e5
C02: French Defense, Advance Variation

324 	1. e4 e6 2. d4 d5 3. e5 c5 4. c3 Nc6 5. Nf3 Bd7
C02: French Defense, Advance Variation - Euwe Variation

325 	1. e4 e6 2. d4 d5 3. Nd2   without 3... c5, 3... Nf6
C03 & C04: French Defense, Tarrasch Variation (incl. Morozevich & Guimard Variations)

326 	1. e4 e6 2. d4 d5 3. Nd2 Nf6
C04-C06: French Defense, Tarrasch Variation with 3... Nf6 (incl. Leningrad & Botvinnik Variations)

327 	1. e4 e6 2. d4 d5 3. Nd2 c5   without 4. exd5
C07: French Defense, Tarrasch Variation - Open System without 4. exd5

328 	1. e4 e6 2. d4 d5 3. Nd2 c5 4. exd5   without 4... exd5
C07: French Defense, Tarrasch Variation - Open System (Chistiakov Defense)

329 	1. e4 e6 2. d4 d5 3. Nd2 c5 4. exd5 exd5
C08: French Defense, Tarrasch Variation - Open System with 4... exd5

330 	1. e4 e6 2. d4 d5 3. Nd2 c5 4. exd5 exd5 5. Ngf3 Nc6
C08 & C09: French Defense, Tarrasch Variation - Open System (Main Line)

331 	1. e4 e6 2. d4 d5 3. Nc3   without 3... Bb4, 3... Nf6
C10: French Defense, Normal Variation - Rubinstein Variation (incl. Fort Knox Variation)

332 	1. e4 e6 2. d4 d5 3. Nc3 dxe4 4. Nxe4 Nd7
C10: French Defense, Normal Variation - Rubinstein Variation (Blackburne Defense)

333 	1. e4 e6 2. d4 d5 3. Nc3 dxe4 4. Nxe4 Nd7 5. Nf3 Ngf6 6. Nxf6+
C10: French Defense, Normal Variation - Rubinstein Variation (Blackburne Defense with 6. Nxf6+)

334 	1. e4 e6 2. d4 d5 3. Nc3 dxe4 4. Nxe4 Nd7 5. Nf3 Ngf6 6. Bg5
C10: French Defense, Normal Variation - Rubinstein Variation (Blackburne Defense with 6. Bg5)

335 	1. e4 e6 2. d4 d5 3. Nc3 dxe4 4. Nxe4 Nd7 5. Nf3 Ngf6 6. Bg5 h6 7. Nxf6+ Nxf6 8. Bh4
C10: French Defense, Normal Variation - Rubinstein Variation (Blackburne Defense with 8. Bh4)

336 	1. e4 e6 2. d4 d5 3. Nc3 Nf6   without 4. Bg5
C11: French Defense, Normal Variation - Classical Variation without 4. Bg5

337 	1. e4 e6 2. d4 d5 3. Nc3 Nf6 4. e5 Nfd7 5. f4 c5 6. Nf3 Nc6 7. Be3 Be7
C11: French Defense, Normal Variation - Classical Variation (Boleslavsky Variation with 7... Be7)

338 	1. e4 e6 2. d4 d5 3. Nc3 Nf6 4. e5 Nfd7 5. f4 c5 6. Nf3 Nc6 7. Be3 cxd4
C11: French Defense, Normal Variation - Classical Variation (Boleslavsky Variation with 7... cxd4)

339 	1. e4 e6 2. d4 d5 3. Nc3 Nf6 4. e5 Nfd7 5. f4 c5 6. Nf3 Nc6 7. Be3 a6
C11: French Defense, Normal Variation - Classical Variation (Boleslavsky Variation with 7... a6)

340 	1. e4 e6 2. d4 d5 3. Nc3 Nf6 4. Bg5   without 4... dxe4
C12-C14: French Defense, Normal Variation (McCutcheon & Classical Variations, incl. Chatard-Alekhine Attack)

341 	1. e4 e6 2. d4 d5 3. Nc3 Nf6 4. Bg5 dxe4
C11: French Defense, Normal Variation - Burn Variation

342 	1. e4 e6 2. d4 d5 3. Nc3 Nf6 4. Bg5 dxe4 5. Nxe4 Be7 6. Bxf6 Bxf6
C11: French Defense, Normal Variation - Burn Variation with 6... Bxf6

343 	1. e4 e6 2. d4 d5 3. Nc3 Bb4
C15 & C16: French Defense, Winawer Variation

344 	1. e4 e6 2. d4 d5 3. Nc3 Bb4 4. e5 c5
C17 & C18: French Defense, Winawer Variation (incl. Bogoljubow & Moscow Variation and Armenian Line)

345 	1. e4 e6 2. d4 d5 3. Nc3 Bb4 4. e5 c5 5. a3 Bxc3+ 6. bxc3 Ne7   without 7. Qg4
C19:  French Defense, Winawer Variation - Main Line

346 	1. e4 e6 2. d4 d5 3. Nc3 Bb4 4. e5 c5 5. a3 Bxc3+ 6. bxc3 Ne7 7. Qg4
C19:  French Defense, Winawer Variation with 7. Qg4 (incl. Poisoned Pawn Variation)

347 	1. e4 e5   without 2. Bc4, 2. Nf3
C20-C22 & C25-C39: Open Games (Early Deviations); Vienna Game; King's Gambit

348 	1. e4 e5 2. Bc4
C23 & C24: Bishop's Opening

349 	1. e4 e5 2. Nf3   without 2... Nc6, 2... Nf6
C40 & C41: Philidor Defense; Latvian Gambit

350 	1. e4 e5 2. Nf3 Nf6   without 3. Nxe5
C42 & C43: Petroff Defense, Three Knights Variation & Modern Attack

351 	1. e4 e5 2. Nf3 Nf6 3. d4 Nxe4 4. Bd3 d5 5. Nxe5
C43: Petroff Defense, Modern Attack (incl. Trifunovic Variation)

352 	1. e4 e5 2. Nf3 Nf6 3. Nxe5
C42: Petroff Defense, incl. Cochrane Gambit, Paulsen & Millennium Attacks and Kaufmann & Lasker Variations

353 	1. e4 e5 2. Nf3 Nf6 3. Nxe5 d6 4. Nf3 Nxe4 5. Nc3
C42: Petroff Defense, Nimzowitsch Attack

354 	1. e4 e5 2. Nf3 Nf6 3. Nxe5 d6 4. Nf3 Nxe4 5. d4
C42: Petroff Defense, Classical Attack (incl. Marshall, Mason & Staunton Variations)

355 	1. e4 e5 2. Nf3 Nf6 3. Nxe5 d6 4. Nf3 Nxe4 5. d4 d5 6. Bd3 Nc6
C42: Petroff Defense, Classical Attack (incl. Berger, Chigorin & Mason-Showalter Variations)

356 	1. e4 e5 2. Nf3 Nf6 3. Nxe5 d6 4. Nf3 Nxe4 5. d4 d5 6. Bd3 Nc6 7. O-O Be7 8. c4
C42: Petroff Defense, Classical Attack - Jaenisch Variation (incl. Browne Attack)

357 	1. e4 e5 2. Nf3 Nf6 3. Nxe5 d6 4. Nf3 Nxe4 5. d4 d5 6. Bd3 Nc6 7. O-O Be7 8. c4 Nb4 9. Be2 O-O 10. Nc3 Bf5
C42: Petroff Defense, Classical Attack - Jaenisch Variation (Main Line with 8... Nb4)

358 	1. e4 e5 2. Nf3 Nc6   without 3. Bc4, 3. Bb5, 3. d4
C44-C47: Ponziani Opening; Three Knights Opening; Four Knights Opening

359 	1. e4 e5 2. Nf3 Nc6 3. d4
C44 & C45: Scotch Game (incl. Mieses, Tartakower & Malaniuk Variations); Goering Gambit; Scotch Gambit

360 	1. e4 e5 2. Nf3 Nc6 3. d4 exd4 4. Nxd4 Nf6 5. Nxc6 bxc6 6. e5 Qe7 7. Qe2 Nd5 8. c4 Ba6
C45: Scotch Game, Mieses Variation with 8... Ba6

361 	1. e4 e5 2. Nf3 Nc6 3. d4 exd4 4. Nxd4 Bc5   without 5. Nxc6
C45: Scotch Game, Classical Variation without 5. Nxc6

362 	1. e4 e5 2. Nf3 Nc6 3. d4 exd4 4. Nxd4 Bc5 5. Nxc6
C45: Scotch Game, Classical Variation with 5. Nxc6

363 	1. e4 e5 2. Nf3 Nc6 3. Bc4   without 3... Nf6
C50-C54: Hungarian Defense; Evans Gambit; Italian Game

364 	1. e4 e5 2. Nf3 Nc6 3. Bc4 Bc5 4. c3 Nf6 5. d3   without 5... a6
C53: Italian Game, Giouco Pianissimo without 5... a6

365 	1. e4 e5 2. Nf3 Nc6 3. Bc4 Bc5 4. c3 Nf6 5. d3 a6
C53: Italian Game, Giouco Pianissimo with 5... a6

366 	1. e4 e5 2. Nf3 Nc6 3. Bc4 Bc5 4. c3 Nf6 5. d3 a6 6. Bb3 d6 7. O-O
C53: Italian Game, Giouco Pianissimo with 5... a6 - Main Line

367 	1. e4 e5 2. Nf3 Nc6 3. Bc4 Nf6   without 4. d3
C55-C59: Two Knights Defense

368 	1. e4 e5 2. Nf3 Nc6 3. Bc4 Nf6 4. d3
C55: Modern Bishop's Opening

369 	1. e4 e5 2. Nf3 Nc6 3. Bb5   without 3... a6, 3... f5, 3... Nf6
C60-C62 & C64: Ruy Lopez, Miscellaneous

370 	1. e4 e5 2. Nf3 Nc6 3. Bb5 f5
C63: Ruy Lopez, Jaenisch/Schliemann Gambit

371 	1. e4 e5 2. Nf3 Nc6 3. Bb5 Nf6   without 4. Nc3, 4. O-O
C65: Ruy Lopez, Berlin Defense (incl. Mortimer & Duras Variations and Nyholm Attack)

372 	1. e4 e5 2. Nf3 Nc6 3. Bb5 Nf6 4. d3 Bc5   without 5. c3
C65: Ruy Lopez, Berlin Defense with 4. d3 Bc5 (incl. Kaufmann Variation)

373 	1. e4 e5 2. Nf3 Nc6 3. Bb5 Nf6 4. d3 Bc5 5. c3
C65: Ruy Lopez, Berlin Defense with 4. d3 Bc5 5.c3 (Main Line)

374 	1. e4 e5 2. Nf3 Nc6 3. Bb5 Nf6 4. Nc3   without 4... Nd4
C48 & C49: Four Knights Game, Spanish Variation without 4... Nd4 (incl. Double Ruy Lopez)

375 	1. e4 e5 2. Nf3 Nc6 3. Bb5 Nf6 4. Nc3 Nd4
C48: Four Knights Game, Spanish Variation - Rubinstein Variation (incl. Marshall Gambit)

376 	1. e4 e5 2. Nf3 Nc6 3. Bb5 Nf6 4. O-O
C64-C67: Ruy Lopez, Berlin Defense with 4. O-O (incl. Improved Steinitz Defense)

377 	1. e4 e5 2. Nf3 Nc6 3. Bb5 Nf6 4. O-O Nxe4 5. d4
C67: Ruy Lopez, Berlin Defense - Rio Gambit Accepted (incl. Rio de Janeiro & L'Hermet Variations) 

378 	1. e4 e5 2. Nf3 Nc6 3. Bb5 Nf6 4. O-O Nxe4 5. d4 Nd6 6. Bxc6 dxc6 7. dxe5 Nf5 8. Qxd8+ Kxd8 9. Nc3 Ne7
C67: Ruy Lopez, Berlin Defense - L'Hermet Variation (Main Line with 9... Ne7)

379 	1. e4 e5 2. Nf3 Nc6 3. Bb5 Nf6 4. O-O Nxe4 5. d4 Nd6 6. Bxc6 dxc6 7. dxe5 Nf5 8. Qxd8+ Kxd8 9. Nc3 Bd7
C67: Ruy Lopez, Berlin Defense - L'Hermet Variation (Main Line with 9... Bd7)

380 	1. e4 e5 2. Nf3 Nc6 3. Bb5 Nf6 4. O-O Nxe4 5. d4 Nd6 6. Bxc6 dxc6 7. dxe5 Nf5 8. Qxd8+ Kxd8 9. Nc3 Ke8
C67: Ruy Lopez, Berlin Defense - L'Hermet Variation (Main Line with 9... Ke8)

381 	1. e4 e5 2. Nf3 Nc6 3. Bb5 a6   without 4. Ba4
C68 & C69: Ruy Lopez, Exchange Variation (Miscellaneous)

382 	1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Bxc6 dxc6 5. O-O   with 5... Bg4, 5... f6
C68 & C69: Ruy Lopez, Exchange Variation with 5. O-O (incl. Alapin Gambit & Gligoric Variation)

383 	1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4   without 4... Nf6
C70-C76: Ruy Lopez, Morphy Defense (Miscellaneous)

384 	1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6   without 5. O-O, 5. d3
C77: Ruy Lopez, Morphy Defense (incl. Wormald & Mackenzie Variations and Exchange Variation Deferred)

385 	1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. d3
C77: Ruy Lopez, Morphy Defense - Anderssen Variation (incl. Duras Variation)

386 	1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. O-O   without 5... Nxe4, 5... Be7
C78 & C79: Ruy Lopez, Morphy Defense - Normal Variation (Miscellaneous)

387 	1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. O-O b5 6. Bb3 Bc5   with 7. d3, 7. c3, 7. a4
C78:  Ruy Lopez, Morphy Defense - Normal Variation (Arkhangelsk Variation)

388 	1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. O-O b5 6. Bb3 Bc5 7. a4 Rb8
C78:  Ruy Lopez, Morphy Defense - Normal Variation (Arkhangelsk Variation - Main Line with 7. a4 Rb8)

389 	1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. O-O Nxe4
C80-C83: Ruy Lopez, Open Variation (Miscellaneous)

390 	1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. O-O Nxe4 6. d4 b5 7. Bb3 d5 8. dxe5 Be6 9. Nbd2
C83:  Ruy Lopez, Open Variation - Bernstein Variation (incl. Karpov Gambit)

391 	1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. O-O Be7   without 6. Re1
C84-C86: Ruy Lopez, Closed Defense without 6. Re1 (Miscellaneous)

392 	1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. O-O Be7 6. d3 b5
C84: Ruy Lopez, Closed Defense with 6. d3 b5

393 	1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. O-O Be7 6. Re1
C87-C88: Ruy Lopez, Closed Defense with 6. Re1 (Miscellaneous)

394 	1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. O-O Be7 6. Re1 b5 7. Bb3 O-O 8. d3   without 8... Bb7
C88 & C90: Ruy Lopez, Closed Defense with 8. d3 (incl. Pilnik Variation)

395 	1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. O-O Be7 6. Re1 b5 7. Bb3 O-O 8. a4   without 8... Bb7
C88: Ruy Lopez, Closed Defense - Anti-Marshall Variation without 8... Bb7

396 	1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. O-O Be7 6. Re1 b5 7. Bb3 O-O 8. a4 Bb7
C88: Ruy Lopez, Closed Defense - Anti-Marshall Variation with 8... Bb7

397 	1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. O-O Be7 6. Re1 b5 7. Bb3 O-O 8. h3
C88: Ruy Lopez, Closed Defense with 8. h3

398 	1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. O-O Be7 6. Re1 b5 7. Bb3 O-O 8. h3 Bb7 9. d3 d6
C88: Ruy Lopez, Closed Defense with 8. h3 Bb7 9. d3 d6 (without 10.a3 Na5)

399 	1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. O-O Be7 6. Re1 b5 7. Bb3 O-O 8. h3 Bb7 9. d3 d6 10. a3 Na5
C88: Ruy Lopez, Closed Defense with 8. h3 Bb7 9. d3 d6 10. a3 Na5

400 	1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. O-O Be7 6. Re1 b5 7. Bb3 O-O 8. c3   without 8... d6
C89: Ruy Lopez, Marshall Attack (Miscellaneous)

401 	1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. O-O Be7 6. Re1 b5 7. Bb3 O-O 8. c3 d5 9. exd5 Nxd5 10. Nxe5 Nxe5 11. Rxe5 c6 12. d4
C89: Ruy Lopez, Marshall Attack with 12. d4 (incl. Geller Variation)

402 	1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. O-O Be7 6. Re1 b5 7. Bb3 d6
C90 & C91: Ruy Lopez, Closed Defense (incl. Yates & Suetin Variations) 

403 	1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. O-O Be7 6. Re1 b5 7. Bb3 d6 8. c3 O-O 9. d4 Bg4 10. d5
C91: Ruy Lopez, Closed Defense - Yates Variation (Bogoljubow Variation with 10. d5)

404 	1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. O-O Be7 6. Re1 b5 7. Bb3 d6 8. c3 O-O 9. h3   without 9... Na5, 9... Nb8, 9... Bb7
C92 & C93: Ruy Lopez, Closed Defense with 9. h3 (incl. Kholmov, Zaitsev, Smyslov & Keres Variations)

405 	1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. O-O Be7 6. Re1 b5 7. Bb3 d6 8. c3 O-O 9. h3 Bb7
C92: Ruy Lopez, Closed Defense - Flohr-Zaitsev Variation without 10. d3 (Miscellaneous)

406 	1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. O-O Be7 6. Re1 b5 7. Bb3 d6 8. c3 O-O 9. h3 Bb7 10. d4 Re8 11. Nbd2 Bf8 12. d5
C92: Ruy Lopez, Closed Defense - Flohr-Zaitsev Variation (Main Line with 12. d5)

407 	1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. O-O Be7 6. Re1 b5 7. Bb3 d6 8. c3 O-O 9. h3 Bb7 10. d4 Re8 11. Nbd2 Bf8 12. a4
C92: Ruy Lopez, Closed Defense - Flohr-Zaitsev Variation (Main Line with 12. a4)

408 	1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. O-O Be7 6. Re1 b5 7. Bb3 d6 8. c3 O-O 9. h3 Nb8
C94 & C95: Ruy Lopez, Closed Defense - Breyer Variation (Miscellaneous)

409 	1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. O-O Be7 6. Re1 b5 7. Bb3 d6 8. c3 O-O 9. h3 Nb8 10. d4 Nbd7 11. Nbd2 Bb7 12. Bc2 Re8 13. Nf1
C95: Ruy Lopez, Closed Defense - Breyer Variation (incl. Romanishin Variation)

410 	1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. O-O Be7 6. Re1 b5 7. Bb3 d6 8. c3 O-O 9. h3 Nb8 10. d4 Nbd7 11. Nbd2 Bb7 12. Bc2 Re8 13. Nf1 Bf8 14. Ng3 g6 15. b3
C95: Ruy Lopez, Closed Defense - Breyer Variation (Main Line with 15. b3)

411 	1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. O-O Be7 6. Re1 b5 7. Bb3 d6 8. c3 O-O 9. h3 Na5
C96: Ruy Lopez, Closed Defense with 9... Na5 (incl. Borisenko & Keres Variations)

412 	1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. O-O Be7 6. Re1 b5 7. Bb3 d6 8. c3 O-O 9. h3 Na5 10. Bc2 c5 11. d4 Qc7
C97: Ruy Lopez, Closed Defense - Chigorin Variation

413 	1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. O-O Be7 6. Re1 b5 7. Bb3 d6 8. c3 O-O 9. h3 Na5 10. Bc2 c5 11. d4 Qc7 12. Nbd2 cxd4 13. cxd4 Nc6
C97: Ruy Lopez, Closed Defense - Chigorin Variation (Classical Variation with 12... cxd4 13. cxd4 Nc6)

414 	1. e4 c5   without 2. Nc3, 2. Nf3, 2. c3
A36, B20 & B21: English Opening - Symmetrical Variation (Botvinnik Variation); Sicilian Defense (Miscellaneous)

415 	1. e4 c5 2. Nc3   without 2... Nc6
B06, B23 & B28: Pirc Defense - Pterodactyl; Sicilian Defense, incl. Grand Prix Variation & Closed Sicilian

416 	1. e4 c5 2. Nc3 Nc6   without 3. Nf3
B23-B26: Sicilian Defense, Closed Sicilian (incl. Traditional, Chameleon, Fianchetto & Vinken Systems)

417 	1. e4 c5 2. c3   without 2... Nf6
B22: Sicilian Defense, Alapin Variation (incl. Barmen Defense with 2... d5)

418 	1. e4 c5 2. c3 d5 3. exd5 Qxd5 4. d4 Nf6 5. Nf3
B22: Sicilian Defense, Alapin Variation - Barmen Defense (Main Lines)

419 	1. e4 c5 2. c3 Nf6
B22: Sicilian Defense, Alapin Variation with 2... Nf6 (Miscellaneous)

420 	1. e4 c5 2. c3 Nf6 3. e5 Nd5 4. Nf3 Nc6
B22: Sicilian Defense, Alapin Variation with 2... Nf6 (incl. Stoltz Attack)

421 	1. e4 c5 2. Nf3   without 2... d6, 2... e6, 2... Nc6
B27-B29: Sicilian Defense with 2. Nf3, incl. O'Kelly & Nimzowitsch Variations and Hyperaccelerated Dragon

422 	1. e4 c5 2. Nf3 Nc6   without 3. Bb5, 3. d4
B30: Sicilian Defense, Old Sicilian (Miscellaneous)

423 	1. e4 c5 2. Nf3 Nc6 3. Nc3 e5
B30: Sicilian Defense, Old Sicilian with 3. Nc3 e5

424 	1. e4 c5 2. Nf3 Nc6 3. Bb5   without 3... d6, 3... g6
B30: Sicilian Defense, Rossolimo Variation (Miscellaneous)

425 	1. e4 c5 2. Nf3 Nc6 3. Bb5 e6 4. O-O
B30: Sicilian Defense, Rossolimo Variation with 3... e6 4. O-O

426 	1. e4 c5 2. Nf3 Nc6 3. Bb5 g6   without 4. Nc3, 4. O-O
B31: Sicilian Defense, Rossolimo Variation with 3... g6 (Miscellaneous)

427 	1. e4 c5 2. Nf3 Nc6 3. Bb5 g6 4. O-O
B31: Sicilian Defense, Rossolimo Variation with 3... g6 4. O-O (incl. Gufeld & Lutikov Gambits and Gurgenidze Variation)

428 	1. e4 c5 2. Nf3 Nc6 3. d4
B32: Sicilian Defense, Old Sicilian (incl. Godiva/Grivas & Flohr Variations)

429 	1. e4 c5 2. Nf3 Nc6 3. d4 cxd4 4. Nxd4 e5
B32: Sicilian Defense, Old Sicilian - La Bourdonnais Variation (incl. Kalashnikov Variation)

430 	1. e4 c5 2. Nf3 Nc6 3. d4 cxd4 4. Nxd4 g6   without 5. c4
B34 & B35: Sicilian Defense, Old Sicilian - Accelerated Dragon

431 	1. e4 c5 2. Nf3 Nc6 3. d4 cxd4 4. Nxd4 g6 5. c4   without 5... Bg7
B36: Sicilian Defense, Maroczy Bind without 5... Bg7 (incl. Gurgenidze Variation)

432 	1. e4 c5 2. Nf3 Nc6 3. d4 cxd4 4. Nxd4 g6 5. c4 Nf6 6. Nc3 d6 7. Be2 Nxd4 8. Qxd4 Bg7 9. Be3
B36: Sicilian Defense, Maroczy Bind - Gurgenidze Variation (Main Line with 9. Be3)

433 	1. e4 c5 2. Nf3 Nc6 3. d4 cxd4 4. Nxd4 g6 5. c4 Bg7
B37-B39:  Sicilian Defense, Maroczy Bind with 5... Bg7 (incl. Breyer Variation)

434 	1. e4 c5 2. Nf3 Nc6 3. d4 cxd4 4. Nxd4 Nf6
B33: Sicilian Defense, Four Knights Variation (incl. Lasker-Pelikan Variation)

435 	1. e4 c5 2. Nf3 Nc6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 e5 6. Ndb5 d6 7. Bg5 a6 8. Na3 b5 9. Bxf6 gxf6 10. Nd5 f5 without 11. Bd3
B33: Sicilian Defense, Lasker-Pelikan Variation - Sveshnikov Variation without 11. Bd3

436 	1. e4 c5 2. Nf3 Nc6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 e5 6. Ndb5 d6 7. Bg5 a6 8. Na3 b5 9. Bxf6 gxf6 10. Nd5 f5 11. Bd3
B33: Sicilian Defense, Lasker-Pelikan Variation - Sveshnikov Variation with 11. Bd3

437 	1. e4 c5 2. Nf3 Nc6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 e5 6. Ndb5 d6 7. Bg5 a6 8. Na3 b5 9. Nd5
B33: Sicilian Defense, Lasker-Pelikan Variation - Chelyabinsk Variation with 9. Nd5

438 	1. e4 c5 2. Nf3 Nc6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 e5 6. Ndb5 d6 7. Bg5 a6 8. Na3 b5 9. Nd5 Be7 10. Bxf6 Bxf6 11. c3
B33: Sicilian Defense, Lasker-Pelikan Variation - Chelyabinsk Variation (Main Line with 11. c3)

439 	1. e4 c5 2. Nf3 Nc6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 e5 6. Ndb5 d6 7. Bg5 a6 8. Na3 b5 9. Nd5 Be7 10. Bxf6 Bxf6 11. c3 Bg5 12. Nc2 O-O 13. a4
B33: Sicilian Defense, Lasker-Pelikan Variation - Chelyabinsk Variation (Main Line with 13. a4)

440 	1. e4 c5 2. Nf3 e6   without 3. c3, 3. d3, 3. d4
B40: Sicilian Defense, French Variation (incl. Kramnik Variation)

441 	1. e4 c5 2. Nf3 e6   with 3. d3, 3. c3
B40: Sicilian Defense, French Variation with 3. d3 & 3. c3

442 	1. e4 c5 2. Nf3 e6 3. d4
B41: Sicilian Defense, French Variation with 3. d4 (incl. Anderssen, Kan & Kveinys Variations)

443 	1. e4 c5 2. Nf3 e6 3. d4 cxd4 4. Nxd4 a6 5. Nc3   without 5... Nc6, 5... Qc7
B43: Sicilian Defense, Paulsen Variation - Kan Variation (Miscellaneous)

444 	1. e4 c5 2. Nf3 e6 3. d4 cxd4 4. Nxd4 a6 5. Nc3 Qc7
B43: Sicilian Defense, Paulsen Variation - Kan Variation with 5... Qc7

445 	1. e4 c5 2. Nf3 e6 3. d4 cxd4 4. Nxd4 a6 5. Bd3   without 5... Bc5, 5... Nf6
B42: Sicilian Defense, Paulsen Variation with 5. Bd3 (incl. Swiss Cheese Variation)

446 	1. e4 c5 2. Nf3 e6 3. d4 cxd4 4. Nxd4 a6 5. Bd3 Nf6
B42: Sicilian Defense, Paulsen Variation with 5. Bd3 Nf6

447 	1. e4 c5 2. Nf3 e6 3. d4 cxd4 4. Nxd4 a6 5. Bd3 Bc5
B42: Sicilian Defense, Paulsen Variation - Polugaevsky Variation

448 	1. e4 c5 2. Nf3 e6 3. d4 cxd4 4. Nxd4 a6 5. Bd3 Bc5 6. Nb3 Be7
B42: Sicilian Defense, Paulsen Variation - Polugaevsky Variation with 6. Nb3 Be7

449 	1. e4 c5 2. Nf3 e6 3. d4 cxd4 4. Nxd4 Nc6   without 5. Nc3
B44: Sicilian Defense, Paulsen Variation - Taimanov-Bastrikov Variation without 5. Nc3 (incl. Szen Variation)

450 	1. e4 c5 2. Nf3 e6 3. d4 cxd4 4. Nxd4 Nc6 5. Nc3   without 5... a6, 5... Qc7
B45: Sicilian Defense, Paulsen Variation - Taimanov-Bastrikov Variation with 5. Nc3 (incl. Four Knights Variation)

451 	1. e4 c5 2. Nf3 e6 3. d4 cxd4 4. Nxd4 Nc6 5. Nc3 a6   without 6. Nxc6
B46: Sicilian Defense, Paulsen Variation - Taimanov-Bastrikov Variation without 6. Nxc6 (incl. Taimanov Variation)

452 	1. e4 c5 2. Nf3 e6 3. d4 cxd4 4. Nxd4 Nc6 5. Nc3 a6 6. Nxc6
B46: Sicilian Defense, Paulsen Variation - Taimanov-Bastrikov Variation with 6. Nxc6

453 	1. e4 c5 2. Nf3 e6 3. d4 cxd4 4. Nxd4 Nc6 5. Nc3 Qc7   without 6. Be3, 6. Be2
B47: Sicilian Defense, Paulsen Variation - Taimanov-Bastrikov Variation (Bastrikov Variation)

454 	1. e4 c5 2. Nf3 e6 3. d4 cxd4 4. Nxd4 Nc6 5. Nc3 Qc7 6. Be2
B47: Sicilian Defense, Paulsen Variation - Taimanov-Bastrikov Variation (Bastrikov Variation with 6. Be2)

455 	1. e4 c5 2. Nf3 e6 3. d4 cxd4 4. Nxd4 Nc6 5. Nc3 Qc7 6. Be3
B48 & B49: Sicilian Defense, Paulsen Variation - Taimanov-Bastrikov Variation (Bastrikov Variation with 6. Be3)

456 	1. e4 c5 2. Nf3 e6 3. d4 cxd4 4. Nxd4 Nc6 5. Nc3 Qc7 6. Be3 a6 7. Qd2
B48: Sicilian Defense, Paulsen Variation - Taimanov-Bastrikov Variation (Bastrikov Variation with 6. Be3 a6 7. Qd2)

457 	1. e4 c5 2. Nf3 d6   without 3. Nc3, 3. Bb5+, 3. d4
B50: Sicilian Defense, Modern Variation - Miscellaneous (incl. Fianchetto & Delayed Alapin)

458 	1. e4 c5 2. Nf3 d6 3. Bb5+   without 3... Nc6, 3... Bd7
B51: Sicilian Defense, Modern Variation - Moscow Variation (Miscellaneous)

459 	1. e4 c5 2. Nf3 d6 3. Bb5+ Nc6
B51: Sicilian Defense, Modern Variation - Moscow Variation with 3... Nc6

460 	1. e4 c5 2. Nf3 d6 3. Bb5+ Nc6 4. O-O Bd7 5. Re1 Nf6 6. c3 a6
B51: Sicilian Defense, Modern Variation - Moscow Variation with 3... Nc6 (Main Line)

461 	1. e4 c5 2. Nf3 d6 3. Bb5+ Bd7
B52: Sicilian Defense, Modern Variation - Moscow Variation (Canal Attack)

462 	1. e4 c5 2. Nf3 d6 3. Bb5+ Bd7 4. Bxd7+ Qxd7 5. c4
B52: Sicilian Defense, Modern Variation - Moscow Variation (Canal Attack - Main Line with 5. c4)

463 	1. e4 c5 2. Nf3 d6 3. d4
B53-B56: Sicilian Defense, Modern Variation with 3. d4 (incl. Chekhover, Moscow & Kupreichik Variations)

464 	1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 g6   without 6. Be3
B70-B74: Sicilian Defense, Dragon Variation without 6. Be3 (incl. Fianchetto, Alekhine & Levenfish Variations)

465 	1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 g6 6. Be3
B72, B75 & B76: Sicilian Defense, Dragon Variation with 6. Be3 (incl. Yugoslav Attack)

466 	1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 g6 6. Be3 Bg7 7. f3 O-O 8. Qd2 Nc6 9. Bc4
B77-B79: Sicilian Defense, Dragon Variation - Yugoslav Attack

467 	1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 e6   without 6. g4
B80, B82, B83 & B86: Sicilian Defense, Scheveningen Variation without 6. g4

468 	1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 e6 6. g4
B81: Sicilian Defense, Scheveningen Variation - Keres Attack

469 	1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 Nc6   without 6. Bg5, 6. Bc4
B56, B58 & B59: Sicilian Defense, Classical Variation (incl. Fianchetto & Boleslavsky Variations)

470 	1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 Nc6 6. Be2 e6
B58: Sicilian Defense, Classical Variation with 6. Be2 e6

471 	1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 Nc6 6. Bc4
B57, B88 & B89: Sicilian Defense, Fischer-Sozin Attack (incl. Velimirovic Attack)

472 	1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 Nc6 6. Bg5   without 6... e6
B60 & B61: Sicilian Defense, Richter-Rauzer Variation (Miscellaneous)

473 	1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 Nc6 6. Bg5 e6
B62 & B63: Sicilian Defense, Richter-Rauzer Variation (incl. Margate, Exchange & Ivanov Variations)

474 	1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 Nc6 6. Bg5 e6 7. Qd2 Be7 8. O-O-O O-O
B63-B65: Sicilian Defense, Richter-Rauzer Variation - Main Line with 7... Be7 8. O-O-O O-O 

475 	1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 Nc6 6. Bg5 e6 7. Qd2 a6
B66: Sicilian Defense, Richter-Rauzer Variation - Main Line with 7... a6 

476 	1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 Nc6 6. Bg5 e6 7. Qd2 a6 8. O-O-O Bd7
B67-B69: Sicilian Defense, Richter-Rauzer Variation - Main Line with 7... a6 8. O-O-O Bd7

477 	1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 a6   without 6. Be3, 6. Bg5, 6. Be2, 6. Bc4, 6. f3, 6. f4, 6. g3
B90: Sicilian Defense, Najdorf Variation (Miscellaneous)

478 	1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 a6   with 6. g3, 6. f3
B90 & B91: Sicilian Defense, Najdorf Variation (incl. Zagreb Variation)

479 	1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 a6 6. f4
B93: Sicilian Defense, Najdorf Variation - Amsterdam Variation

480 	1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 a6 6. Bc4
B87 & B90: Sicilian Defense, Najdorf Variation - Lipnitzky Variation (incl. Flank Variation)

481 	1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 a6 6. Bg5
B94-B96: Sicilian Defense, Najdorf Variation with 6. Bg5 (incl. Polugaevsky Variation)

482 	1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 a6 6. Bg5 e6 7. f4   with 7... Nbd7, 7... Be7
B96, B98 & B99: Sicilian Defense, Najdorf Variation with 6. Bg5 e6 7. f4 (incl. Browne Variation)

483 	1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 a6 6. Bg5 e6 7. f4 Qb6
B97: Sicilian Defense, Najdorf Variation - Poisoned Pawn Variation

484 	1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 a6 6. Be2   without 6... e5
B84 & B92: Sicilian Defense, Najdorf Variation - Opocensky Variation; Classical Scheveningen - Maroczy Variation

485 	1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 a6 6. Be2 e6 7. O-O
B84 & B85: Sicilian Defense, Classical Scheveningen - Maroczy Variation with 7. O-O

486 	1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 a6 6. Be2 e6 7. O-O Be7 8. f4 O-O 9. Kh1
B85: Sicilian Defense, Classical Scheveningen - Maroczy Variation with 7. O-O Be7

487 	1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 a6 6. Be2 e6 7. O-O Be7 8. f4 O-O 9. Kh1 Qc7 10. a4 Nc6 11. Be3 Re8 12. Bf3
B85: Sicilian Defense, Classical Scheveningen - Maroczy Variation (Main Line)

488 	1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 a6 6. Be2 e5
B92: Sicilian Defense, Najdorf Variation - Opocensky Variation with 6... e5

489 	1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 a6 6. Be2 e5 7. Nb3 Be7 8. O-O O-O   without 9. Kh1
B92: Sicilian Defense, Najdorf Variation - Opocensky Variation with 6... e5 (Main Line without 9. Kh1)

490 	1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 a6 6. Be2 e5 7. Nb3 Be7 8. O-O O-O 9. Kh1
B92: Sicilian Defense, Najdorf Variation - Opocensky Variation with 6... e5 (Main Line with 9. Kh1)

491 	1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 a6 6. Be3   without 6... e6, 6... e5
B90: Sicilian Defense, Najdorf Variation - English Attack (Miscellaneous)

492 	1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 a6 6. Be3 e6   without 7. Be2, 7. f3
B81 & B90: Sicilian Defense, Najdorf Variation - English Attack (incl. Delayed Keres Attack & Perenyi Gambit)

493 	1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 a6 6. Be3 e6 7. f3
B80: Sicilian Defense, Scheveningen Variation - English Attack with 6... e6 7. f3

494 	1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 a6 6. Be3 e6 7. f3 b5 8. g4 h6
B80: Sicilian Defense, Scheveningen Variation - English Attack with 6... e6 7. f3 b5 8. g4 h6

495 	1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 a6 6. Be3 e5   without 7. Nb3
B90: Sicilian Defense, Najdorf Variation - English Attack with 6... e5

496 	1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 a6 6. Be3 e5 7. Nf3 Be7
B90: Sicilian Defense, Najdorf Variation - English Attack with 6... e5 7. Nf3 Be7

497 	1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 a6 6. Be3 e5 7. Nb3
B90: Sicilian Defense, Najdorf Variation - English Attack with 6... e5 7. Nb3

498 	1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 a6 6. Be3 e5 7. Nb3 Be6 8. f3
B90: Sicilian Defense, Najdorf Variation - English Attack with 6... e5 7. Nb3 Be6 8. f3

499 	1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 a6 6. Be3 e5 7. Nb3 Be6 8. f3 Nbd7 9. Qd2   without 9... b5
B90: Sicilian Defense, Najdorf Variation - English Attack with 6... e5 7. Nb3 Be6 8. f3 Nbd7 9. Qd2

500 	1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 a6 6. Be3 e5 7. Nb3 Be6 8. f3 Nbd7 9. Qd2 b5
B90: Sicilian Defense, Najdorf Variation - English Attack with 6... e5 7. Nb3 Be6 8. f3 Nbd7 9. Qd2 b5

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