ecocodes
Volume C · Open games and the French Defense‹ C39C41 ›
a1b2c3d4e5f6g7h8
Reference position · Black to move

C40 King’s Knight Opening

Also filed here: Latvian Gambit, King’s Pawn Game, Elephant Gambit, Gunderam Defense.

C40 holds 40 named lines from five openings, most of them (25) under Latvian Gambit. It leaves C20 (King’s Pawn Game) with 2.Nf3. Material is no longer level at the end of 14 of its lines; the widest gap, five pawns in White’s favour, comes in Latvian Gambit: Corkscrew Gambit. Lines of 60 other codes continue from its position, the second-widest spread of the 100 codes in volume C.

Score sheet
#WhiteBlack
1e4e5
2Nf3

The move that completes C40

The reference line of C41 plays all of these moves and continues beyond them; C40 is the position reached at 2.Nf3.

  1. 2.Nf3 The knight leaves g1 for f3, opening a line for the rook on h1.

Lines filed under C40

All 40 share their first three plies, the whole reference line and then split seven ways at Black’s move 2.

NameAfter the shared startPliesAt the end
King’s Knight Opening(the shared start itself)3
Elephant Gambit2...d54
Gunderam Defense2...Qe74
King’s Pawn Game: Busch-Gass Gambit2...Bc54
King’s Pawn Game: Damiano Defense2...f64
King’s Pawn Game: Gunderam Gambit2...c64
King’s Pawn Game: McConnell Defense2...Qf64
Latvian Gambit2...f54
Latvian Gambit Accepted2...f5 3.exf55White +1
Latvian Gambit: Diepstraten Countergambit2...f5 3.c45
Latvian Gambit: Lobster Gambit2...f5 3.g45
Latvian Gambit: Mason Countergambit2...f5 3.d45
Latvian Gambit: Mayet Attack2...f5 3.Bc45
Latvian Gambit: Mlotkowski Variation2...f5 3.Nc35
Latvian Gambit: Senechaud Gambit2...f5 3.b45
Elephant Gambit: Maróczy Gambit2...d5 3.exd5 Bd66White +1
Elephant Gambit: Paulsen Countergambit2...d5 3.exd5 e46White +1
King’s Pawn Game: Busch-Gass Gambit, Chiodini Gambit2...Bc5 3.Nxe5 Nc66White +1
King’s Pawn Game: Gunderam Defense, Gunderam Gambit2...Qe7 3.Bc4 f56
Latvian Gambit: Fraser Defense2...f5 3.Nxe5 Nc66White +1
Latvian Gambit: Greco Variation2...f5 3.Nxe5 Qe76White +1
Latvian Gambit: Mayet Attack, Morgado Defense2...f5 3.Bc4 Nf66
Latvian Gambit: Mayet Attack, Strautins Gambit2...f5 3.Bc4 b56
King’s Pawn Game: La Bourdonnais Gambit2...Qf6 3.Bc4 Qg6 4.O-O7White castled
Latvian Gambit Accepted: Foltys-Leonhardt Variation2...f5 3.Nxe5 Qf6 4.Nc47White +1
Latvian Gambit Accepted: Main Line2...f5 3.Nxe5 Qf6 4.d47White +1
Elephant Gambit: Wasp Variation2...d5 3.Nxe5 dxe4 4.Bc4 Qg58
King’s Pawn Game: Damiano Defense, Damiano Gambit, Chigorin Gambit2...f6 3.Nxe5 Qe7 4.Nf3 d58White +1
Latvian Gambit: Corkscrew Countergambit2...f5 3.Bc4 fxe4 4.Nxe5 Nf68
Latvian Gambit: Mayet Attack, Polerio-Svedenborg Variation2...f5 3.Bc4 fxe4 4.Nxe5 d58
Latvian Gambit Accepted: Bilguer Variation2...f5 3.Nxe5 Qf6 4.d4 d6 5.Nc49White +1
Latvian Gambit Accepted: Foltys Variation2...f5 3.Nxe5 Qf6 4.Nc4 fxe4 5.d39
Latvian Gambit Accepted: Leonhardt Variation2...f5 3.Nxe5 Qf6 4.Nc4 fxe4 5.Nc39
Latvian Gambit: Mayet Attack, Poisoned Pawn Variation2...f5 3.Bc4 fxe4 4.Nxe5 Qg5 5.d4 Qxg210Black +1
King’s Pawn Game: Damiano Defense, Damiano Gambit2...f6 3.Nxe5 fxe5 4.Qh5+ g6 5.Qxe5+ Qe7 6.Qxh811White +4
Latvian Gambit Accepted: Bronstein Attack2...f5 3.Nxe5 Qf6 4.d4 d6 5.Nc4 fxe4 6.Be211
Latvian Gambit Accepted: Nimzowitsch Attack2...f5 3.Nxe5 Qf6 4.d4 d6 5.Nc4 fxe4 6.Ne311
Latvian Gambit: Corkscrew Gambit2...f5 3.Nxe5 Nf6 4.Bc4 fxe4 5.Nf7 Qe7 6.Nxh8 d512White +5
Latvian Gambit Accepted: Bronstein Gambit2...f5 3.Nxe5 Qf6 4.d4 d6 5.Nc4 fxe4 6.Qh5+ g6 7.Qe213
Latvian Gambit: Behting Variation2...f5 3.Bc4 fxe4 4.Nxe5 Qg5 5.Nf7 Qxg2 6.Rf1 d5 7.Nxh8 Nf614White +4

The road to C40

  1. 1.e4B00 King’s Pawn Game
  2. 1...e5C20 King’s Pawn Game
  3. 2.Nf3C40

The position after 2.Nf3

White has brought out the knight on f3; Black has not yet moved a knight or bishop. Black is to move and has 29 legal moves.

WhiteBlackMaterial (pawn units)3939Minor pieces developed10Moves spent on pawns11Pawns on d4, e4, d5, e511Squares attacked in the other half65not castlednot castled

Codes that branch off from C40

The reference lines of three other codes leave C40 from the position after 2.Nf3, each with its own moves.

CodeMovesReference line
C412...d6Philidor Defense
C422...Nf6Petrov’s Defense
C442...Nc6King’s Knight Opening: Normal Variation

Closest boards in other codes

CodeLineDiffers on
C34King’s Gambit Accepted: King’s Knight’s Gambitthree squares: f2, f4, e5
A04Zukertort Openingfour squares: e2, e4, e5, e7
B00King’s Pawn Gamefour squares: g1, f3, e5, e7
B27Sicilian Defensefour squares: c5, e5, c7, e7
B40Sicilian Defense: French Variationfour squares: c5, e5, e6, c7
C00French Defensefour squares: g1, f3, e5, e6
C23Bishop’s Openingfour squares: f1, g1, f3, c4

Where lines continue from here

Besides the codes above, they belong to C27, C43, C45, C46, C47, C48, C49, C50, C51, C52, C53, C54, C55, C56, C57, C58, C59, C60, C61, C62, C63, C64, C65, C66, C67, C68, C69, C70, C71, C72, C73, C74, C75, C76, C77, C78, C79, C80, C81, C82, C83, C84, C85, C86, C87, C88, C89, C90, C91, C92, C93, C94, C95, C96, C97, C98, C99.

Volume C

  1. 00
  2. 01
  3. 02
  4. 03
  5. 04
  6. 05
  7. 06
  8. 07
  9. 08
  10. 09
  11. 10
  12. 11
  13. 12
  14. 13
  15. 14
  16. 15
  17. 16
  18. 17
  19. 18
  20. 19
  21. 20
  22. 21
  23. 22
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  25. 24
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  31. 30
  32. 31
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  34. 33
  35. 34
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  38. 37
  39. 38
  40. 39
  41. 40
  42. 41
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  44. 43
  45. 44
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  47. 46
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  54. 53
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  100. 99

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