Chessy
Semi-Slav Defense: Bf4 – A Comfortable Edge for Black
The Semi-Slav Defense: Bf4 (ECO D43) starts with 1.d4 d5 2.c4 c6 3.Nf3 Nf6 4.Nc3 e6 5.Bf4. When White develops the bishop to f4, you strike with 5...dxc4 — grabbing a pawn and immediately asking White to prove they have compensation. Stockfish evaluates this position at -0.38, a small edge in your favour. The database backs that up: across over 37,000 games, Black wins 48.1% of the time, nearly identical to White's 48.3%. Below you'll face this exact position against an adapting engine. Your task: hold the extra pawn, develop your pieces, and convert that small plus into a full point.
Play the Semi-Slav Defense: Bf4 against the engine
Free, no signup — you play black, the engine adapts to your level.
Now it's your turn. Play the position from 5...dxc4 against the adapting engine and prove you can handle Black's small edge. Create a free account to track your
Create a free account →Why 5...dxc4 Works So Well
By capturing on c4, you challenge White's central setup immediately. White's bishop on f4 has left the queenside a bit vulnerable — they cannot recapture the pawn with 6.e3? because 6...b5 traps the bishop or wins back the pawn on better terms. That's why the engine's best reply is the clever 6.a4, preventing ...b5 and preparing to develop the bishop to b4. The statistics show that Black scores well against every White response, but especially against 6.e4 (White scores just 45.7% there) and 6.Bg5 (White scores only 44.1%). You've already achieved equality at minimum — and the engine says you have a slight pull.
Handling White's Most Popular Move: 6.e3
The move 6.e3 is played in nearly half of all games (17,561 out of 37,228), but it's actually an inaccuracy that loses about half a pawn compared to 6.a4. White intends to recapture the pawn with Bxc4, but you have time to develop actively. You can play ...b5 to hold the pawn, or simply continue development with ...Be7, ...0-0, and ...Nbd7, remaining solid. White scores 50.0% against this move — essentially no advantage despite having the extra tempo. Recognise 6.e3 as a minor slip and keep your calm. Your position is already slightly better.
Punishing the Inaccuracies: a3 and h3
Two other common mistakes are 6.a3 and 6.h3. Both are inaccuracies, losing about 0.5-0.6 pawns compared to the correct 6.a4. After 6.a3, White wastes a tempo preventing ...Bb4, but your dark-squared bishop often finds a good home on e7 or d6 anyway, and you can play ...b5 to secure your pawn on c4. After 6.h3, White spends time stopping ...Ng4, which wasn't an immediate threat. In both cases, follow the same plan: hold the pawn with ...b5, complete your development, and enjoy the pressure. The engine prefers you; trust the position.
What the Drill Will Test
In this interactive session, you play Black from the position after 5...dxc4 with White to move. The engine will adapt to your skill level, but it knows the best reply is 6.a4. If White plays 6.e3, 6.a3, or 6.h3, you've already gained a measurable edge. Focus on two things: holding onto the extra pawn (or returning it only for clear development) and getting your pieces active. Your king will castle kingside, your bishop will find a diagonal, and your knight on f6 is already well placed. The statistics show Black winning just as often as White here — prove the engine right.
Results across 37,228 Lichess games
| Most-played continuation | Games | White wins |
|---|---|---|
| e3 | 17,561 | 50.0% |
| e4 | 13,327 | 45.7% |
| a4 | 4,154 | 50.6% |
| a3 | 848 | 49.5% |
| h3 | 421 | 47.7% |
| Bg5 | 245 | 44.1% |
Frequently asked questions
Is 5...dxc4 the only good move in the Semi-Slav Bf4?
Yes, it is the thematic and best reply. By taking on c4 you immediately unbalance the position. The engine's evaluation of -0.38 confirms you get a small edge as Black, while other moves like 5...Be7 or 5...Nbd7 are playable but don't challenge White as effectively.
What should Black do after 6.a4?
After 6.a4, the engine's top continuation is 6...Bb4, pinning the knight on c3. White then usually plays 7.g3 followed by 8...a5, challenging your b4-bishop. You remain solid: the pawn on c4 is safe, your pieces are developing naturally, and you still have a slight edge according to the engine.
Should Black try to keep the pawn on c4?
Generally yes — holding the pawn is a central part of the opening's idea. You can support it with ...b5 if White doesn't play 6.a4 immediately. Just be careful not to overextend or fall behind in development. If White plays accurately, you may eventually give it back for active play, but the engine trusts your position either way.
Why is 6.e3 an inaccuracy for White?
Stockfish evaluates 6.e3 as losing about half a pawn compared to 6.a4. White wants to recapture on c4 with the bishop, but this gives you time to secure the pawn with ...b5 or simply complete your development. White's score of 50.0% from this move confirms they gain no advantage despite having the move.
How many games feature the Semi-Slav Defense: Bf4?
Over 37K Lichess games have reached the Semi-Slav Defense: Bf4 position. White wins 48.3%, Black wins 48.1%, with 3.6% draws — based on real rated games.