ecocodes
Volume E · Indian defenses‹ E00E02 ›
a1b2c3d4e5f6g7h8
Reference position · Black to move

E01 Catalan Opening: Open Defense

E01 holds two named lines, all under the name Catalan Opening. It leaves E00 (Catalan Opening) with 4.Bg2. Lines of eight other codes continue from its position, the second-widest spread of the 10 Catalan Opening codes. At seven plies, its reference line is the second-shortest of the 10 Catalan Opening codes. Black, to move in that position, has 32 legal moves, the fifth-lowest count of the 10 Catalan Opening codes.

Score sheet
#WhiteBlack
1d4Nf6
2c4e6
3g3d5
4Bg2

The move that completes E01

The reference line of E02 plays all of these moves and continues beyond them; E01 is the position reached at 4.Bg2.

  1. 4.Bg2 The bishop leaves f1 for g2, guarding the rook on h1.

Lines filed under E01

Both share their first seven plies, the whole reference line.

NameAfter the shared startPlies
Catalan Opening: Open Defense(the shared start itself)7
Catalan Opening: Tarrasch Defense4...c5 5.Nf3 Nc610

Catalan Opening: Tarrasch Defense

  1. 4...c5 The c-pawn advances two squares to c5, covering b4 and d4, opening a line for the queen on d8.
  2. 5.Nf3 The knight leaves g1 for f3, opening a line for the rook on h1.
  3. 5...Nc6 The knight leaves b8 for c6, opening a line for the rook on a8.

The road to E01

  1. 1.d4 … 2...e6three earlier stops: A40, A45, A50
  2. 3.g3E00 Catalan Opening
  3. 3...d5E00 Catalan Opening
  4. 4.Bg2E01

The position after 4.Bg2

White has brought out the bishop on g2; Black the knight on f6. Black could capture with dxc4. Undefended and attacked: the pawn on c4.

WhiteBlackMaterial (pawn units)3939Minor pieces developed11Moves spent on pawns32Pawns on d4, e4, d5, e511Squares attacked in the other half65not castlednot castled

Codes that branch off from E01

The reference lines of two other codes leave E01 from the position after 4.Bg2, each with its own moves.

CodeMovesReference line
E024...dxc4Catalan Opening: Open Defense
E064...Be7 5.Nf3Catalan Opening: Closed

Closest boards in other codes

CodeLineDiffers on
A90Dutch Defense: Classical Variationfour squares: d5, f5, d7, f7
E04Catalan Opening: Open Defensefour squares: g1, f3, c4, d5
D30Queen’s Gambit Declinedfive squares: f1, g2, g3, f6, g8
D35Queen’s Gambit Declined: Normal Defensefive squares: b1, f1, g2, c3, g3
E03Catalan Opening: Open Defensefive squares: d1, c4, d5, d7, b8
A91Dutch Defense: Classical Variationsix squares: d5, f5, d7, e7, f7, f8
E05Catalan Opening: Open Defense, Classical Linesix squares: g1, f3, c4, d5, e7, f8

Where lines continue from here

Besides the codes above, they belong to E03, E04, E05, E07, E08, E09.

Volume E

  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 Catalan Opening codes