A39 English Opening: Symmetrical Variation, Mecking Variation
A39 holds a single named line. It leaves A38 (English Opening: Symmetrical Variation, Full Symmetry Line) with 6.O-O O-O 7.d4. At 13 plies, its reference line is the longest of the 29 English Opening codes. Both kings have castled by the end of the reference line, White on move 6 and Black on move 6. No other English Opening code shares this. Black has three minor pieces off their first squares, level for the most of the 29 English Opening codes.
| # | White | Black |
|---|---|---|
| 1 | c4 | Nf6 |
| 2 | Nf3 | c5 |
| 3 | Nc3 | Nc6 |
| 4 | g3 | g6 |
| 5 | Bg2 | Bg7 |
| 6 | O-O | O-O |
| 7 | d4 |
Moves only A39 plays
Same as A38 up to 5...Bg7, then:
- 6.O-O White castles kingside, opening a line for the queen on d1, guarding the bishop on g2.
- 6...O-O Black castles kingside, opening a line for the queen on d8, guarding the bishop on g7.
- 7.d4 The d-pawn advances two squares to d4, covering c5 and e5, opening a line for the bishop on c1 and the queen on d1.
The road to A39
Two of the six named positions on the way are reached by a move order other than their own.
- 1.c4 … 3.Nc3four earlier stops: A10, A15, A34
- 3...Nc6A35 Four Knights Variation by another order
- 5...Bg7A38 Full Symmetry Line
- 7.d4A39
The position after 7.d4
White has brought out the knight on c3, knight on f3 and bishop on g2; Black the knight on c6, knight on f6 and bishop on g7. Black could capture with Nxd4, cxd4. Black is to move and has 31 legal moves.
Closest boards in other codes
| Code | Line | Differs on |
|---|---|---|
| E65 | King’s Indian Defense: Fianchetto Variation, Yugoslav Variation | four squares: c6, d6, d7, b8 |
| E66 | King’s Indian Defense: Fianchetto Variation, Yugoslav Variation, Advance Line | four squares: d4, d5, d6, d7 |
| A89 | Dutch Defense: Leningrad Variation, Matulovic Variation | six squares: c5, f5, d6, c7, d7, f7 |
| D75 | Neo-Grünfeld Defense: Delayed Exchange Variation | six squares: c4, d5, c6, f6, d7, b8 |
| E63 | King’s Indian Defense: Fianchetto Variation, Panno Variation | six squares: c5, a6, d6, a7, c7, d7 |
| A63 | Benoni Defense: Fianchetto Variation, Hastings Defense | seven squares: c4, d4, d5, c6, d6, d7, e7 |
| A88 | Dutch Defense: Leningrad Variation, Warsaw Variation | seven squares: c5, f5, c6, d6, d7, f7, b8 |