ecocodes
Volume D · Closed and semi-closed games‹ D15D17 ›
a1b2c3d4e5f6g7h8
Reference position · Black to move

D16 Slav Defense: Alapin Variation

D16 holds four named lines, all under the name Slav Defense. It leaves D15 (Slav Defense: Two Knights Attack) with 5.a4. When the reference line ends, Black is one pawn up on material. Lines of three other codes continue from its position, the fourth-widest spread of the 10 Slav Defense codes. Black, to move in that position, has 33 legal moves, the fifth-highest count of the 10 Slav Defense codes.

Score sheet
#WhiteBlack
1d4d5
2c4c6
3Nf3Nf6
4Nc3dxc4
5a4

The move that completes D16

The reference line of D17 plays all of these moves and continues beyond them; D16 is the position reached at 5.a4.

  1. 5.a4 The a-pawn advances two squares to a4, covering b5, opening a line for the rook on a1.

Lines filed under D16

All four share their first nine plies, the whole reference line and then split three ways at Black’s move 5.

NameAfter the shared startPliesAt the end
Slav Defense: Alapin Variation(the shared start itself)9Black +1
Slav Defense: Smyslov Variation5...Na610Black +1
Slav Defense: Soultanbeieff Variation5...e610Black +1
Slav Defense: Steiner Variation5...Bg410Black +1

Slav Defense: Smyslov Variation

  1. 5...Na6 The knight leaves b8 for a6, opening a line for the rook on a8.

Slav Defense: Soultanbeieff Variation

  1. 5...e6 The e-pawn advances to e6, covering d5 and f5, opening a line for the queen on d8 and the bishop on f8.

Slav Defense: Steiner Variation

  1. 5...Bg4 The bishop leaves c8 for g4, opening a line for the queen on d8, attacking the knight on f3.

The road to D16

  1. 1.d4 … 3...Nf6five earlier stops: A40, D00, D06, D10, D11
  2. 4.Nc3D15 Three Knights Variation
  3. 4...dxc4D15 Two Knights Attack
  4. 5.a4D16

The position after 5.a4

White has brought out the knight on c3 and knight on f3; Black the knight on f6. White has a half-open c-file; Black a half-open d-file. Black could capture with Qxd4.

WhiteBlackMaterial (pawn units)3839Minor pieces developed21Moves spent on pawns33Pawns on d4, e4, d5, e510Squares attacked in the other half66Doubled pawns01not castlednot castled

Codes that branch off from D16

The reference lines of one other code leave D16 from the position after 5.a4, each with its own moves.

CodeMovesReference line
D175...Bf5Slav Defense: Czech Variation

Closest boards in other codes

CodeLineDiffers on
D18Slav Defense: Czech Variation, Classical Systemfour squares: e2, e3, f5, c8
D24Queen’s Gambit Accepted: Showalter Variationfour squares: a2, a4, c6, c7
D23Queen’s Gambit Acceptedsix squares: b1, a2, c3, a4, c6, c7
D43Semi-Slav Defensesix squares: a2, a4, c4, d5, e6, e7
D44Semi-Slav Defense Acceptedsix squares: c1, a2, a4, g5, e6, e7
D13Slav Defense: Exchange Variationseven squares: b1, a2, c3, a4, c4, d5, c6
A31English Opening: Symmetrical Variation, Anti-Benoni Variationeight squares: b1, a2, c3, a4, c4, c5, c6, d7

Where lines continue from here

Besides the codes above, they belong to D18, D19.

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
  20. 19
  21. 20
  22. 21
  23. 22
  24. 23
  25. 24
  26. 25
  27. 26
  28. 27
  29. 28
  30. 29
  31. 30
  32. 31
  33. 32
  34. 33
  35. 34
  36. 35
  37. 36
  38. 37
  39. 38
  40. 39
  41. 40
  42. 41
  43. 42
  44. 43
  45. 44
  46. 45
  47. 46
  48. 47
  49. 48
  50. 49
  51. 50
  52. 51
  53. 52
  54. 53
  55. 54
  56. 55
  57. 56
  58. 57
  59. 58
  60. 59
  61. 60
  62. 61
  63. 62
  64. 63
  65. 64
  66. 65
  67. 66
  68. 67
  69. 68
  70. 69
  71. 70
  72. 71
  73. 72
  74. 73
  75. 74
  76. 75
  77. 76
  78. 77
  79. 78
  80. 79
  81. 80
  82. 81
  83. 82
  84. 83
  85. 84
  86. 85
  87. 86
  88. 87
  89. 88
  90. 89
  91. 90
  92. 91
  93. 92
  94. 93
  95. 94
  96. 95
  97. 96
  98. 97
  99. 98
  100. 99

Open this line in the finderAll Slav Defense codes