A42 Modern Defense: Averbakh System
Also filed here: Pterodactyl Defense.
A42 holds six named lines from two openings, most of them (four) under Modern Defense. It leaves A41 (Modern Defense) with 4.e4. None of its six lines contains a capture. That final move, by the e-pawn, covers d5 and f5 and opens a line for the queen on d1 and the bishop on f1.
| # | White | Black |
|---|---|---|
| 1 | d4 | g6 |
| 2 | c4 | Bg7 |
| 3 | Nc3 | d6 |
| 4 | e4 |
Moves only A42 plays
Same as A40 up to 1.d4, then:
- 1...g6 The g-pawn advances to g6, covering f5 and h5, opening a line for the bishop on f8.
- 2.c4 The c-pawn advances two squares to c4, covering b5 and d5, opening a line for the queen on d1.
- 2...Bg7 The bishop leaves f8 for g7, guarding the rook on h8.
- 3.Nc3 The knight leaves b1 for c3, opening a line for the rook on a1.
- 3...d6 The d-pawn advances to d6, covering c5 and e5, opening a line for the bishop on c8 and the queen on d8.
- 4.e4 The e-pawn advances two squares to e4, covering d5 and f5, opening a line for the queen on d1 and the bishop on f1.
Lines filed under A42
They begin with two different first moves.
| Name | After the shared start | Plies |
|---|---|---|
| Modern Defense: Averbakh System | 1.d4 g6 2.c4 Bg7 3.Nc3 d6 4.e4 | 7 |
| Modern Defense: Kotov Variation | 1.d4 g6 2.c4 Bg7 3.Nc3 d6 4.e4 Nc6 | 8 |
| Modern Defense: Randspringer Variation | 1.d4 g6 2.c4 Bg7 3.Nc3 d6 4.e4 f5 | 8 |
| Modern Defense: Averbakh Variation, Pseudo-Sämisch | 1.d4 g6 2.c4 Bg7 3.e4 d6 4.Be3 Nf6 5.f3 | 9 |
| Pterodactyl Defense | 1.Nf3 c5 2.c4 g6 3.d4 Bg7 4.e4 Qa5+ 5.Nc3 d6 | 10 |
| Pterodactyl Defense: Central, Bogolubovia | 1.d4 g6 2.c4 Bg7 3.e4 d6 4.Nc3 c5 5.Nge2 Qa5 | 10 |
The road to A42
- 1.d4one earlier stop: A40
- 1...g6A40 Modern Defense
- 3...d6A41 Modern Defense
- 4.e4A42
The position after 4.e4
White has brought out the knight on c3; Black the bishop on g7. Black could capture with Bxd4. Black is to move and has 32 legal moves.
Closest boards in other codes
| Code | Line | Differs on |
|---|---|---|
| E70 | King’s Indian Defense: Normal Variation | four squares: d6, f6, d7, g8 |
| E71 | King’s Indian Defense: Makogonov Variation | four squares: h2, h3, f6, g8 |
| E72 | King’s Indian Defense: Normal Variation, Deferred Fianchetto | four squares: g2, g3, f6, g8 |
| E73 | King’s Indian Defense: Normal Variation, Standard Development | four squares: f1, e2, f6, g8 |
| E76 | King’s Indian Defense: Four Pawns Attack | four squares: f2, f4, f6, g8 |
| E80 | King’s Indian Defense: Sämisch Variation | four squares: f2, f3, f6, g8 |
| E90 | King’s Indian Defense: Normal Variation, Rare Defenses | four squares: g1, f3, f6, g8 |