ecocodes
Volume D · Closed and semi-closed games‹ D36D38 ›
a1b2c3d4e5f6g7h8
Reference position · Black to move

D37 Queen’s Gambit Declined: Three Knights Variation

D37 holds 15 named lines, all under the name Queen’s Gambit. It leaves E10 (Indian Defense: Anti-Nimzo-Indian) with 3...d5 4.Nc3. Lines filed under D24, D60, D63 and E14 reach one of its named positions by a different move order. With 15 named lines it is the third-largest code of the 44 Queen’s Gambit codes. Lines of 20 other codes continue from its position, the fourth-widest spread of the 44 Queen’s Gambit codes.

Score sheet
#WhiteBlack
1d4Nf6
2c4e6
3Nf3d5
4Nc3

The move that completes D37

The reference line of D38 plays all of these moves and continues beyond them; D37 is the position reached at 4.Nc3.

  1. 4.Nc3 The knight leaves b1 for c3, opening a line for the rook on a1.

Lines filed under D37

All 15 share the start 1.d4 and then split two ways at Black’s move 1.

NameAfter the shared startPliesAt the end
Queen’s Gambit Declined: Three Knights Variation1...Nf6 2.c4 e6 3.Nf3 d5 4.Nc37
Queen’s Gambit Declined: Barmen Variation1...Nf6 2.c4 e6 3.Nf3 d5 4.Nc3 Nbd78
Queen’s Gambit Declined: Three Knights, Vienna Variation1...Nf6 2.c4 e6 3.Nf3 d5 4.Nc3 dxc48Black +1
Queen’s Gambit Declined: Harrwitz Attack1...Nf6 2.c4 e6 3.Nf3 d5 4.Nc3 Be7 5.Bf49
Queen’s Gambit Declined: Vienna Variation, Quiet Variation1...Nf6 2.c4 e6 3.Nf3 d5 4.Nc3 dxc4 5.e39Black +1
Queen’s Gambit Declined: Three Knights Variation1...d5 2.c4 e6 3.Nc3 Nf6 4.Nf3 Be7 5.e3 O-O10Black castled
Queen’s Gambit Declined: Miles Variation1...Nf6 2.c4 e6 3.Nf3 d5 4.Nc3 Be7 5.Bg5 O-O 6.Qc211Black castled
Queen’s Gambit Declined: Harrwitz Attack, Fianchetto Defense1...d5 2.c4 e6 3.Nc3 Be7 4.Nf3 Nf6 5.Bf4 O-O 6.e3 b612Black castled
Queen’s Gambit Declined: Harrwitz Attack, Orthodox Defense1...d5 2.c4 e6 3.Nc3 Nf6 4.Nf3 Be7 5.Bf4 O-O 6.e3 c612Black castled
Queen’s Gambit Declined: Harrwitz Attack, Two Knights Defense1...Nf6 2.c4 e6 3.Nf3 d5 4.Nc3 Be7 5.Bf4 O-O 6.e3 Nbd712Black castled
Queen’s Gambit Declined: Knight Defense, Alekhine Gambit1...Nf6 2.c4 e6 3.Nf3 d5 4.Nc3 Nbd7 5.Bg5 h6 6.Bh4 dxc412Black +1
Queen’s Gambit Declined: Harrwitz Attack, Two Knights Defense, Blockade Line1...Nf6 2.c4 e6 3.Nc3 d5 4.Nf3 Be7 5.Bf4 O-O 6.e3 Nbd7 7.c513Black castled
Queen’s Gambit Declined: Harrwitz Attack, Main Line1...Nf6 2.c4 e6 3.Nf3 d5 4.Nc3 Be7 5.Bf4 O-O 6.e3 c5 7.dxc5 Bxc514Black castled
Queen’s Gambit Declined: Harrwitz Attack1...Nf6 2.c4 e6 3.Nf3 d5 4.Nc3 Be7 5.Bf4 O-O 6.e3 c5 7.dxc5 Bxc5 8.Qc2 Nc6 9.Rd1 Qa5 10.a319Black castled
Queen’s Gambit Declined: Harrwitz Attack1...Nf6 2.c4 e6 3.Nf3 d5 4.Nc3 Be7 5.Bf4 O-O 6.e3 c5 7.dxc5 Bxc5 8.Qc2 Nc6 9.a3 Qa5 10.O-O-O19both castled

The road to D37

  1. 1.d4 … 1...Nf6two earlier stops: A40, A45
  2. 2.c4A50 Normal Variation
  3. 3.Nf3E10 Anti-Nimzo-Indian
  4. 4.Nc3D37

The position after 4.Nc3

White has brought out the knight on c3 and knight on f3; Black the knight on f6. Black could capture with dxc4. Undefended and attacked: the pawn on c4. Black is to move and has 32 legal moves.

WhiteBlackMaterial (pawn units)3939Minor pieces developed21Moves spent on pawns22Pawns on d4, e4, d5, e511Squares attacked in the other half65not castlednot castled

Codes that branch off from D37

The reference lines of two other codes leave D37 from the position after 4.Nc3, each with its own moves.

CodeMovesReference line
D384...Bb4Queen’s Gambit Declined: Ragozin Defense
D404...c5Queen’s Gambit Declined: Semi-Tarrasch Defense

Closest boards in other codes

CodeLineDiffers on
D35Queen’s Gambit Declined: Normal Defensetwo squares: g1, f3
D43Semi-Slav Defensetwo squares: c6, c7
B14Caro-Kann Defense: Panov Attackfour squares: g1, e2, f3, c7
D15Slav Defense: Three Knights Variationfour squares: c6, e6, c7, e7
D24Queen’s Gambit Accepted: Showalter Variationfour squares: c4, d5, e6, e7
D31Queen’s Gambit Declined: Queen’s Knight Variationfour squares: g1, f3, f6, g8
D41Queen’s Gambit Declined: Semi-Tarrasch Defensefour squares: c4, c5, d5, c7

Where lines continue from here

Besides the codes above, they belong to D24, D35, D36, D39, D41, D42, D44, D53, D55, D56, D58, D60, D62, D63, D64, D65, D67, D68.

Volume D

  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
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  21. 20
  22. 21
  23. 22
  24. 23
  25. 24
  26. 25
  27. 26
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  30. 29
  31. 30
  32. 31
  33. 32
  34. 33
  35. 34
  36. 35
  37. 36
  38. 37
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  40. 39
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  44. 43
  45. 44
  46. 45
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  64. 63
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  90. 89
  91. 90
  92. 91
  93. 92
  94. 93
  95. 94
  96. 95
  97. 96
  98. 97
  99. 98
  100. 99

Other move orders

  • Queen’s Gambit Declined: Three Knights Variation is also reached inside D24 Queen’s Gambit Accepted, whose order is 1.d4 d5 2.c4 e6 3.Nf3 Nf6 4.Nc3.
  • Queen’s Gambit Declined: Three Knights Variation is also reached inside D60 Queen’s Gambit Declined: Orthodox Defense, Rauzer Variation, whose order is 1.d4 d5 2.Nf3 Nf6 3.c4 e6 4.Nc3.
  • Queen’s Gambit Declined: Three Knights Variation is also reached inside D63 Queen’s Gambit Declined: Orthodox Defense, Capablanca Variation, whose order is 1.Nf3 d5 2.d4 Nf6 3.c4 e6 4.Nc3.
  • Queen’s Gambit Declined: Three Knights Variation is also reached inside E14 Queen’s Indian Defense, with e3, whose order is 1.d4 Nf6 2.c4 e6 3.Nf3 d5 4.e3 Be7 5.Nc3 O-O.
  • Queen’s Gambit Declined: Three Knights, Vienna Variation is also reached inside D24 Queen’s Gambit Accepted, whose order is 1.d4 d5 2.c4 e6 3.Nf3 Nf6 4.Nc3 dxc4.

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