Modern Defense
Initial Moves: 1.e4 g6 2.d4 Bg7 3.Nc3 d6
Strategic Summary & Main Idea
The Modern Defence puts the bishop on g7 before anything else and delays the decision about the g8 knight, the c-pawn and the e-pawn. It is the most flexible defence against 1.e4, and the flexibility has a measured price: after 3...d6 the position is +0.69, practically the same as the Pirc. What the entry shows is where that number moves. The immediate 4.f4 Nf6 5.e5, which looks crushing, measures 0.00 after 5...Nfd7 6.Nf3 c5; the Pterodactyl, with ...c5 and ...Qa5, reaches +1.26; and the Monkey's Bum, White's famous gambit, measures −1.25.
The pawn structure this opening produces
The Modern starts with no defined structure, and that is the strategy. With pawns on g6 and d6 and the bishop on g7, Black lets White occupy e4 and d4 and waits to see which set-up White chooses before committing the rest. If White plays c4, the structure becomes an Averbakh, a relative of the King's Indian, and the right break is ...e5 with the knight on c6 or d7; if White pushes d5, the game closes and Black looks for ...f5. If White castles long with Be3, Qd2 and f3, the answer is expansion with ...a6, ...b5 and sometimes ...c5, opening the wing where the White king lives. In the ...c6 and ...d5 version, the Gurgenidze Variation, the structure changes family: it becomes a Caro-Kann with the bishop on g7, and White gains space with e5. What Black cannot do is release the centre early without reason: ...e5 met by dxe5 and a queen trade leaves the Black king in the centre and the d-file open for White's rook. The flexibility only pays while no Black pawn has been pushed without a plan.
Typical Plans for White
- Set up Be3, Qd2 and f3 and castle long, with h4-h5 against the castled king or the wing where Black's king will stay
- Play c4 and transpose to the Averbakh, where White's space is larger and Black needs ...e5
- Do not push e5 early against ...Nf6: 5.e5 Nfd7 6.Nf3 c5 measures 0.00
- Against an immediate ...c5, take on c5 and accept an open game the g7 bishop cannot exploit alone
- Avoid the Monkey's Bum: giving up d4 for an attack on f7 measures −1.25
Typical Plans for Black
- Wait for White's choice before committing knight and pawns: ...a6 and ...b5 against long castling
- Against c4, play ...Nc6 and ...e5 and close the centre to play ...f5 later
- Against Be3, do not exchange on e5 early: the queen trade with a castling check measures +1.30
- Keep a retreat square for the f6 knight for when e5 comes, and answer with ...c5 against d4
- Do not jump to g4 with the knight against Be3 and Qd2: Bg5 and the ...h6-g5 advance leave holes on the kingside
Main Variations of the Modern Defense
| Variation | Move Sequence | Evaluation | Style / Characteristic |
|---|---|---|---|
| Line with f4 and ...b5 | 1.e4 g6 2.d4 Bg7 3.Nc3 d6 4.f4 a6 5.Nf3 b5 6.Bd3 |
+0.74 | The Austrian set-up against queenside expansion |
| 150 Attack (4.Be3) | 1.e4 g6 2.d4 Bg7 3.Nc3 d6 4.Be3 a6 5.Qd2 Nd7 6.f3 b5 |
+0.64 | Long castling against ...b5; Black keeps the g8 knight at home |
| Averbakh System (3.c4) | 1.e4 g6 2.d4 Bg7 3.c4 d6 4.Nc3 Nc6 5.Be3 e5 6.d5 Nce7 |
+0.73 | A closed centre in King's Indian style, with ...f5 as Black's plan |
| Gurgenidze Variation (3...c6) | 1.e4 g6 2.d4 Bg7 3.Nc3 c6 4.f4 d5 5.e5 h5 |
+0.91 | A Caro-Kann with the bishop on g7; White gains too much space |
| Tiger's Modern (4.Nf3 a6) | 1.e4 g6 2.d4 Bg7 3.Nc3 d6 4.Nf3 a6 5.a4 b6 |
+0.73 | Black waits with ...a6 and ...b6; a4 stops ...b5 and the waiting goes on |
| Pterodactyl (3...c5 4.c3 Qa5) | 1.e4 g6 2.d4 Bg7 3.Nf3 c5 4.c3 Qa5 |
+1.26 | The queen comes out early to pin c3; the highest White evaluation in the entry |
| Line with 3.Nf3 and 4.Bc4 | 1.e4 g6 2.d4 Bg7 3.Nf3 d6 4.Bc4 c6 5.O-O |
+0.49 | White's classical development and the lowest evaluation among the normal lines |
| 4.f4 Nf6 5.e5 Nfd7 | 1.e4 g6 2.d4 Bg7 3.Nc3 d6 4.f4 Nf6 5.e5 Nfd7 6.Nf3 c5 |
0.00 | The push that looks like a refutation leaves the centre unsupported against ...c5 |
Evaluations measured by us with Stockfish 19, depth 22, on 15/09/2026.
Frequently asked questions
Is the Modern Defence weaker than the Pirc?
Not by the measurement: the Modern is +0.69 after 3...d6 and the Pirc +0.73 after 3...g6. The difference is within the noise. What changes is the repertoire: the Modern avoids the Austrian with the knight on f6, but allows White set-ups with c4 that the Pirc does not.
Is the e5 push dangerous for Black in the Modern?
Only if Black does not react against d4. After 4.f4 Nf6 5.e5 Nfd7 6.Nf3 c5, the position is 0.00: the e5 pawn has lost the support of the d4 pawn, and the g7 bishop starts biting on the centre. The push that seems to gain space hands over White's whole advantage.
Does the Pterodactyl work?
It is the highest White evaluation in this entry, +1.26 after 3.Nf3 c5 4.c3 Qa5. The queen comes out early, White completes development with gain of time and the c5 pawn pressures nothing that is not already defended. It works as a surprise, not as a main defence.
Common Mistakes & Where Most Amateurs Go Wrong
- 01 Breaking with ...e5 against the 150 Attack before being ready. After 5.dxe5 dxe5 6.Qxd8+ Kxd8 7.O-O-O+, the Black king has lost castling, the d-file belongs to White and the position rises from +0.69 to +1.30. The line:
1.e4 g6 2.d4 Bg7 3.Nc3 d6 4.Be3 e5 5.dxe5 dxe5 6.Qxd8+ Kxd8 7.O-O-O++1.30 - 02 Attacking the bishop with 5...Ng4 against Be3 and Qd2. After 6.Bg5 h6 7.Bh4 g5 8.Bg3, the knight has achieved nothing and the advanced g- and h-pawns have opened the kingside: +1.07. The line:
1.e4 g6 2.d4 Bg7 3.Nc3 d6 4.Be3 Nf6 5.Qd2 Ng4 6.Bg5 h6 7.Bh4 g5 8.Bg3+1.07 - 03 Playing the Monkey's Bum as White: 2.Bc4 Bg7 3.Qf3 e6 4.d4 Bxd4 5.Ne2 Bg7 6.Nbc3. The d4 pawn has been given for an attack on f7 that does not exist, and Black is better: −1.25. The line:
1.e4 g6 2.Bc4 Bg7 3.Qf3 e6 4.d4 Bxd4 5.Ne2 Bg7 6.Nbc3−1.25
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