Chessy
How to Play the Indian Defense: Accelerated London System with 3.d5
After the moves 1.d4 Nf6 2.Bf4 c5 3.d5, you have set up the key pawn thrust of the Accelerated London System as White. You've closed the centre early, sidestepping many sharp Sicilian-style lines. The position is still a fight — Black has several ways to respond, and the statistics show a real battle ahead. Stockfish gives you +0.45, a small edge for White, so you are slightly better. But the practical results across over 90,000 games tell a more cautious story: Black actually wins more often than White. Your challenge is to convert that engine edge into a real score. That starts with knowing the main replies and how to meet them — and the interactive drill below will help you train exactly that.
Play the Indian Defense: Accelerated London System: c5 against the engine
Free, no signup — you play white, the engine adapts to your level.
Start the interactive drill below and train your responses against 3…d6, 3…e6, 3…Qb6, and the tricky 3…c4. Practice the exact engine lines and build the muscle
Create a free account →What You're Fighting For: The d5 Pawn Wedge
Your move 3.d5 creates a space advantage and takes away the square e4 from Black's knight on f6. This pawn wedge also restricts Black's light-squared bishop and makes it harder for Black to develop naturally with …d6 or …e5. If Black ever captures on d5, you recapture with the e-pawn (or the queen after …exd5), opening lines for your pieces while keeping a central majority. Your main long-term plan is straightforward: develop your knights to c3 and f3, castle kingside, and then decide whether to push e4 or play on the queenside with c4 and b4. The engine's recommended line after Black's best reply — 3…d6 4.Nc3 e5 5.Bg5 — shows you pinning the knight and keeping the centre closed, which suits White's space advantage.
The Engine's Answer to Black's Best Move: 3…d6
The most popular move in the position is 3…d6, played nearly 40,000 times. Stockfish's top continuation is 4.Nc3. After 4…e5, White plays 5.Bg5, pinning the knight and threatening to double Black's pawns if …h6 is played. This is a patient approach: you don't rush to open the centre, you just improve your pieces and maintain the bind. Notice that after 5.Bg5, Black's dark-squared bishop is stuck behind its own pawns, and Black cannot easily challenge your pawn on d5. If Black plays 5…h6, you can simply retreat 6.Bh4 and keep the pressure — Black's pawn on h6 can become a long-term target if you later castle kingside and attack with g4 or h4.
The Major Responses and What They Mean for You
Black has several credible alternatives to 3…d6. Here is what your plans should be against each one, based on the statistics and Stockfish's assessment. 3…e6 (over 15,700 games, White scores 47%): Black immediately challenges the centre. The most principled reply is 4.Nc3, and if 4…exd5 5.Nxd5, you have a comfortable position with active piece play. 3…Qb6 (over 13,400 games, White scores only 41.6%): Black attacks the b2 pawn and the d4 square. This is Black's most dangerous try. You should defend b2 with 4.Nc3 or 4.Qc1, and be ready to meet …Qxb2 with Rb1, trapping the queen. 3…b5 (nearly 6,000 games, White scores 44.6%): A wing gambit. Accepting the pawn with 4.Bxb5+ is fine, but you can also simply develop with 4.Nc3 and maintain your centre. 3…g6 (almost 5,000 games, White scores 44.3%): Black fianchettos. Play 4.Nc3 Bg7 5.e4 d6 and you have a favourable version of a King's Indian Defence where Black's c5 pawn is a weakness. 3…c4 (over 3,000 games, White scores a strong 52.9%): This is actually a mistake (see the next section). You should meet it with 4.e3, and if 4…Qb6, then 5.Nc3 with excellent play.
The One Mistake to Punish: 3…c4
The database and engine agree that 3…c4 is an inaccuracy that loses about 0.8 pawns of evaluation. It looks like Black is trying to grab space on the queenside, but in reality this pawn becomes weak. Your best response is 4.e3, threatening to take it with Bxc4, or simply 4.Nc3 followed by e3. After 4.e3, if Black defends with …Qb6 or …b5, you can play 5.b3 anyway — Black's pawn on c4 is overextended and will fall. The statistics bear this out: White scores 52.9% from this position, your best result against any Black reply. If you see your opponent play 3…c4, you should be confident — your winning chances are notably higher than usual.
Results across 90,081 Lichess games
| Most-played continuation | Games | White wins |
|---|---|---|
| d6 | 39,305 | 45.9% |
| e6 | 15,727 | 47.0% |
| Qb6 | 13,480 | 41.6% |
| b5 | 5,927 | 44.6% |
| g6 | 4,863 | 44.3% |
| c4 | 3,098 | 52.9% |
Frequently asked questions
Is 1.d4 Nf6 2.Bf4 c5 the same as the Benoni Defence?
No, this is specifically the Accelerated London System. In a standard Benoni, White plays 2.c4 or 2.Nf3 and allows Black to set up a full Benoni structure. Here, with 2.Bf4 and then 3.d5, White prevents …d5 and creates a different pawn centre. The positions can look similar, but White's bishop on f4 gives extra control over the e5 square.
What is White's main plan after 3.d5?
Your main plan is to complete development with Nc3, Nf3, e4, and castle kingside. The pawn on d5 gives you a space advantage. You can later decide whether to push e4-e5 for a kingside attack, or play b4 to undermine Black's queenside. Against most Black setups, keeping the centre closed and slowly improving is the right approach.
Why does Black have a higher win rate than White if the engine says +0.45?
The engine evaluation +0.45 reflects optimal play from both sides, but in real games White often makes mistakes converting the small edge. Black's win rate of 50.8% suggests that this position is trickier to navigate as White than it looks. Common errors include mishandling the …Qb6 attack on b2, or pushing pawns prematurely. Use the drill below to practice the key responses and improve your practical results.
Is 3…c4 really a mistake? It looks like a useful space-gaining move.
Yes, the engine considers 3…c4 an inaccuracy — it loses about 0.8 pawns. The pawn on c4 looks aggressive, but it cannot be maintained and becomes a target. White can attack it with b3 or simply develop and let Black spend moves defending it. The database shows White scoring 52.9% after 3…c4, your best result in this line.
How many games feature the Indian Defense: Accelerated London System: c5?
Over 90K Lichess games have reached the Indian Defense: Accelerated London System: c5 position. White wins 46.1%, Black wins 50.8%, with 3.1% draws — based on real rated games.