Chessy
Nimzowitsch Defense: Williams Variation — 3.Bb5
The Nimzowitsch Defense is a fighting choice for Black right from move one — instead of occupying the centre with 1...e5, you challenge the game with 1...Nc6. The Williams Variation with 3.Bb5 is an especially tricky line, and here you're going to learn exactly what to expect when White pins your knight. The key moment comes on move four: after 1.e4 Nc6 2.Nf3 d6 3.Bb5 a6, White must decide how to handle the bishop. The statistics across over 24,000 games show this is a razor-thin edge for White, and your best chance to equalise lies in knowing the engine-approved follow-up. Jump into the drill below to test your understanding against an adapting opponent.
Play the Nimzowitsch Defense: Williams Variation: Bb5 against the engine
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Create a free account →The Critical Moment: 3...a6
After 1.e4 Nc6 2.Nf3 d6, White's bishop lands on b5, pinning your knight. Your response, 3...a6, asks the bishop a simple question: trade or retreat? This is the branching point of the variation. From here, Stockfish assesses the position at +0.51, a small advantage for White, meaning you are slightly worse as Black. That's not a disaster — it's a normal, playable imbalance for a fighting opening. The real test comes next: which continuation do you face most often, and how should you react?
Facing White's Best: Bxc6+
The engine's top choice is 4.Bxc6+, and this is also what White plays most frequently — 13,320 games in the database. The point is clear: White gives up the bishop pair to damage your queenside pawn structure. After 4...bxc6, White follows with 5.d4 Nf6, reaching a position where you have the two bishops as compensation for the doubled c-pawns. White wins 53.1% of games from this position; you win 42.7%. That slight scoring gap matches the evaluation — you are slightly worse, but the doubled pawns are not as crippling as they look. Your extra bishop pair and central control (with ...e5 or ...Bg4 ideas) give real counterplay.
The Most-Played Alternatives (and Which to Punish)
Not every White player knows the engine's recommendation. The second-most common move is 4.Ba4 (10,021 games), but the engine flags this as an inaccuracy that loses roughly 0.6 pawns — White should have taken on c6. Your ideal reply is ...b5, chasing the bishop and gaining time. Even more tempting for you: 4.O-O appears in 85 games, and it is a genuine blunder, losing about 4.6 pawns. If your opponent castles early, you can punish them immediately. 4.Bc4 (724 games) is also marked as an inaccuracy (again losing ~0.6 pawns). In all these cases, knowing the right answer in the drill will let you seize an edge.
What the Numbers Tell You
Across all 24,387 games from the 3...a6 position, White scores 53.1% — a real but modest advantage. When White plays the engine's preferred Bxc6+, White's winning percentage drops slightly to 52.9%. That's a tiny difference, but it confirms you are not in a desperate position. Your 42.7% win rate as Black is healthy for a sound but slightly worse opening. By contrast, if White plays the inaccurate 4.Ba4, their score rises to 53.9% — but only because many Black players don't know the best reply. Learn it here, and you can flip those numbers.
Results across 24,387 Lichess games
| Most-played continuation | Games | White wins |
|---|---|---|
| Bxc6+ | 13,320 | 52.9% |
| Ba4 | 10,021 | 53.9% |
| Bc4 | 724 | 52.6% |
| Be2 | 89 | 42.7% |
| O-O | 85 | 41.2% |
| d4 | 34 | 44.1% |
Frequently asked questions
Is the Nimzowitsch Defense: Williams Variation good for Black?
It's a playable but slightly worse opening. Stockfish evaluates it at +0.51 in White's favour, and White scores 53.1% across 24,387 games. You are slightly worse, but the position offers real counterplay, especially if White does not know the best moves.
What is the best move for White against 3...a6?
The engine's top choice is 4.Bxc6+, which trades the bishop for your knight and doubles your c-pawns. White then follows with d4 and Nf3, reaching a position with a small but stable advantage. This is also White's most-played move (13,320 games).
How should Black respond if White plays 4.Ba4?
4.Ba4 is an inaccuracy that loses about 0.6 pawns compared to Bxc6+. You should immediately chase the bishop with 4...b5, gaining time and space on the queenside. The bishop then has to move again, and you can follow up with ...Nf6 or ...Bb7 with comfortable play.
What happens if White castles on move four?
4.O-O is a blunder, losing about 4.6 pawns. You can punish it with ...Nf6 or ...Bg4, developing with tempo, or simply take the initiative in the centre. The engine says White should have played 4.Be2 instead, so if you see O-O, strike back.