Chessy
Modern Defense: Standard Defense with Bg5 — Playing for Black
The Modern Defense is for players who like to tease their opponent into overreaching. After 1.e4 g6 2.d4 Bg7 3.Nc3 d6 4.Bg5, you play 4...a6 — a flexible waiting move that says, what are you going to do about my king's bishop? The engine evaluates the position at +0.52, a small edge for White, meaning you are slightly worse but very much in the fight. What makes this line special is how often White's natural-looking replies backfire: the statistics show you actually score well when White gets impatient. Dive into the interactive drill below to learn the critical ideas and punish your opponent's most common mistakes.
Play the Modern Defense: Standard Defense: Bg5 against the engine
Free, no signup — you play black, the engine adapts to your level.
Set up the position for Black and play through the drill below. The engine will adapt to your moves so you can practise the key ideas until they feel automatic.
Create a free account →What You're Fighting For — Positional Flexibility
With the move 4...a6, you aren't threatening anything immediate. Instead, you're taking the b5-square away from White's pieces and waiting to see how they commit. Your main long-term idea is a hypermodern one: let White occupy the centre with pawns, then chip away at it with moves like ...b5, ...c5, or ...e5, while your fianchettoed bishop on g7 exerts pressure along the long diagonal. At +0.52, White has a slight edge, but the position remains rich with imbalance — your counterplay will come from exploiting the dark squares and the open lines that appear once White advances. Because you play Black, you are the reactive side, and many White players lose their way before reaching a clear plan.
The Engine's Best Continuation — a4
Stockfish's top choice is 5.a4, preparing to develop the knight to e2 and keep your b5 advance in check. After 5...Nc6 6.Nge2 h6, the engine sees a solid but unspectacular position. If your opponent plays a4, you should be patient: develop your knight to c6, then challenge the centre with moves like ...e5 or ...Be6. This line is only played in a tiny fraction of games, so most opponents will choose something else — and that's where things get interesting for you.
White's Most Common Replies and What They Mean
Here are the most-played moves White tries in practice, along with what the statistics suggest about each one: Nf3 (1,193 games, White scores 50.7%) — A natural developing move that keeps the position balanced. White has no edge here; you should respond with ...Nc6 or ...b5 and play normally. Qd2 (861 games, White scores 49.1%) — White scores below 50%! Your set-up neutralises Qd2 well; consider ...b5 followed by ...Bb7. Bc4 (391 games, White scores 55.5%) — This is the one popular move you need to be careful against. White targets f7 early, and the statistics say you are worse here. Prepare to defend the f7-square carefully. f4 (275 games, White scores 53.1%) — White tries to storm the kingside, but the engine calls this an inaccuracy. e5 (108 games, White scores 44.4%) — White rushes to open lines and is punished: they score under 45%. Bd3 (96 games, White scores 49.0%) — Another developing move that the engine treats as a mistake.
The Mistakes to Punish — f4, e5, and Bd3
Three white moves that look aggressive or natural are actually errors you can exploit: f4 is an inaccuracy costing about 0.6 pawns — White weakens the kingside dark squares and neglects development. You can reply with ...Nc6 or ...b5 and prepare to meet White's pawn storm with ...e5, opening the long diagonal for your bishop. e5 is a full mistake, losing roughly 1.6 pawns. White opens the centre prematurely, and your pieces are well placed to counter: ...dxe5, then ...Nc6, and your dark-squared bishop becomes a monster. Bd3 is also a mistake costing around 1.4 pawns — it blocks the d-pawn and wastes a tempo. A quick ...c5 or ...b5 lets you seize the initiative. When you see any of these three moves from your opponent, you know you've already achieved a better position out of the opening.
Results across 3,495 Lichess games
| Most-played continuation | Games | White wins |
|---|---|---|
| Nf3 | 1,193 | 50.7% |
| Qd2 | 861 | 49.1% |
| Bc4 | 391 | 55.5% |
| f4 | 275 | 53.1% |
| e5 | 108 | 44.4% |
| Bd3 | 96 | 49.0% |
Frequently asked questions
Is the Modern Defense: Standard Defense Bg5 a good opening for beginners?
Yes, it's a fine choice for beginners who want to practise playing against a broad centre. You don't need to memorise long forcing lines. The opening teaches you important ideas: fianchetto development, waiting moves, and counter-attacking when the opponent overextends. Just be ready to defend accurately if White plays Bc4 early.
How should Black respond if White plays 5.Bc4 ?
Bc4 is the most dangerous popular move for you — White scores 55.5% from it. You should prepare to meet the threat to f7. A standard response is ...e6, blocking the diagonal and preparing ...Nc6 or ...Ne7. Be careful not to weaken the dark squares unnecessarily, and castle quickly when safe.
Why is 5.e5 a mistake for White?
White opens the centre too early, losing about 1.6 pawns according to the engine. After 5...dxe5, your dark-squared bishop on g7 gains a powerful open diagonal, and your pieces develop naturally with ...Nc6. White's premature advance has handed you an excellent position.
What is the best way to play against 5.a4 ?
The engine's top move, 5.a4, is designed to stop your ...b5 advance. You can play ...Nc6, developing and eyeing the d4 pawn, followed by ...h6 asking White what the bishop intends. If the bishop retreats, you can continue with ...e5 or ...Be6, maintaining the hypermodern tension.