D27 Queen’s Gambit Accepted: Classical Defense, Main Line
D27 holds seven named lines, all under the name Queen’s Gambit. It leaves D26 (Queen’s Gambit Accepted: Classical Defense, Normal Line) with 6...a6. That final move, by the a-pawn, covers b5 and opens a line for the rook on a8. Of all other reference positions, the board of D28 (Queen’s Gambit Accepted: Classical Defense, Alekhine System) comes closest, two squares apart.
| # | White | Black |
|---|---|---|
| 1 | d4 | d5 |
| 2 | c4 | dxc4 |
| 3 | Nf3 | Nf6 |
| 4 | e3 | e6 |
| 5 | Bxc4 | c5 |
| 6 | O-O | a6 |
Lines filed under D27
All seven share the start 1.d4 d5 2.c4 dxc4 and then split two ways at White’s move 3.
| Name | After the shared start | Plies | At the end |
|---|---|---|---|
| Queen’s Gambit Accepted: Classical Defense, Main Line | 3.Nf3 Nf6 4.e3 e6 5.Bxc4 c5 6.O-O a6 | 12 | White castled |
| Queen’s Gambit Accepted: Classical Defense, Main Line | 3.Nf3 Nf6 4.e3 e6 5.Bxc4 c5 6.O-O a6 7.Nc3 | 13 | White castled |
| Queen’s Gambit Accepted: Classical Defense, Rubinstein Variation | 3.Nf3 Nf6 4.e3 e6 5.Bxc4 c5 6.O-O a6 7.a4 | 13 | White castled |
| Queen’s Gambit Accepted: Classical Defense, Russian Gambit | 3.e3 Nf6 4.Bxc4 e6 5.Nf3 c5 6.O-O a6 7.e4 | 13 | White castled |
| Queen’s Gambit Accepted: Furman Variation | 3.Nf3 Nf6 4.e3 e6 5.Bxc4 c5 6.O-O a6 7.dxc5 Bxc5 | 14 | White castled |
| Queen’s Gambit Accepted: Classical Defense, Main Line | 3.Nf3 Nf6 4.e3 e6 5.Bxc4 a6 6.Nc3 b5 7.Bb3 Bb7 8.O-O c5 | 16 | White castled |
| Queen’s Gambit Accepted: Classical Defense, Rubinstein Variation | 3.Nf3 e6 4.e3 Nf6 5.Bxc4 Be7 6.O-O O-O 7.Nc3 a6 8.a4 c5 | 16 | both castled |
The road to D27
- 1.d4 … 5.Bxc4eight earlier stops: A40, D00, D06, D20, D21, D23, D25, D26
- 5...c5D26 Classical Defense
- 6.O-OD26 Normal Line
- 6...a6D27
The position after 6...a6
White has brought out the knight on f3 and bishop on c4; Black the knight on f6. White has a half-open c-file; Black a half-open d-file. White could capture with Bxa6, Bxe6, dxc5. White is to move and has 36 legal moves.
Codes that branch off from D27
The reference lines of one other code leave D27 from the position after 6...a6, each with its own moves.
| Code | Moves | Reference line |
|---|---|---|
| D28 | 7.Qe2 | Queen’s Gambit Accepted: Classical Defense, Alekhine System |
Closest boards in other codes
| Code | Line | Differs on |
|---|---|---|
| D29 | Queen’s Gambit Accepted: Classical Defense, Alekhine System, Main Line | seven squares: d1, e2, b3, c4, b5, b7, c8 |
| E54 | Nimzo-Indian Defense: Normal Variation, Gligoric System, Exchange Variation | nine squares: b1, c3, b4, a6, a7, e8, f8, g8 … |
| D05 | Queen’s Pawn Game: Colle System | 11 squares: e1, f1, g1, h1, c2, c4, c5, d5 … |
| D25 | Queen’s Gambit Accepted: Normal Variation | 11 squares: e1, f1, g1, h1, c4, c5, a6, e6 … |
| E55 | Nimzo-Indian Defense: Normal Variation, Gligoric System, Bronstein Variation | 11 squares: b1, c3, b4, a6, a7, d7, b8, e8 … |
| A31 | English Opening: Symmetrical Variation, Anti-Benoni Variation | 12 squares: e1, f1, g1, h1, e2, e3, c4, a6 … |
| D19 | Slav Defense: Czech Variation, Dutch Variation | 12 squares: b1, a2, c3, a4, b4, c5, f5, a6 … |
Where lines continue from here
Six named lines filed under other codes pass through the position after 6...a6. Besides the codes above, they belong to D29.