Chessy
Black's Survival Guide: Modern Defense, Mongredien Defense with Nf3 Bd3
You're trying the Modern Defense, but White has already played 3.Nf3 and 4.Bd3 — a direct setup aiming at your king. Now after 4...b6 and 5...c5, you've reached the Mongredien Defense, and Stockfish sees the position as +1.06, a clear edge for White. That means you are noticeably worse right out of the opening. Don't panic — the statistics across over 1,100 games show Black still wins 43.8% of the time. The trick is knowing exactly where White's advantage lies and how to steer toward the least punishing continuation. The interactive drill below will help you build that survival instinct.
Play the Modern Defense: Mongredien Defense, with Nf3: Bd3 against the engine
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Ready to practise handling the Mongredien Defense as Black? Start the interactive drill below — the engine will adapt to your moves and help you find the right
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In this Mongredien line, White's early Bd3 eyes the h7 square, and with the pawn on e4 and the knight on f3, a quick kingside attack is the threat. You've played ...b6 to fianchetto your own light-squared bishop, but the problem is that White's centre — d4 and e4 — is strong and unopposed. Your ...c5 push challenges the centre, but it also leaves your d-pawn backward and the d5 square weak. The engine wants White to play 6.c3, reinforcing the centre and preparing to meet your ...Ba6 with O-O, then trade bishops. Your job is to find counterplay before White's space advantage becomes crushing. The key idea: develop your queenside quickly, trade off White's dangerous dark-squared bishop if possible, and don't waste time on inaccurate pawn moves or premature castling.
The Engine's Top Move: 6.c3
The most accurate move for White here is 6.c3 (played in 402 of 1,108 games). It supports d4, stops ...b4 ideas, and keeps the centre solid. Against it, the engine's plan is simple: develop with 6...Ba6, challenging White's Bd3 — a typical Modern Defense idea. After 7.O-O Bxd3 8.Qxd3, you've traded off your potentially bad bishop for White's active one. The queen on d3 isn't threatening you much, and you can continue with ...d6, ...Nd7, and maybe ...e6 or ...Nf6. White's score after 6.c3 is 53.7% — solid but not crushing. You're still worse, but the position is playable if you keep your king safe and aim for a slow, maneuvering game.
Which Moves to Avoid (and Why)
Two moves here lose significant ground and are confirmed inaccuracies by the engine. 6.e5 (played 47 times) loses about 0.8 pawns of advantage — it weakens the d5 square and lets you challenge the centre with ...d6 or ...Nh6 without much risk. White's score after e5 is 53.2%, but the evaluation gap is bigger than that suggests. 6.O-O (played 58 times) is an inaccuracy that loses about 0.5 pawns. It might look natural, but it lets you play ...cxd4 7.Nxd4 Ba6, trading bishops without White getting compensation. White's score after O-O drops to exactly 50.0% — completely even. So if you see White castle early here, you're in good shape. The most punishing reply to either mistake is to grab the initiative with ...cxd4 and ...Ba6 immediately.
What the Numbers Tell You
Across 1,108 games from this exact position, the scoreboard reads: White wins 52.1%, draws 4.2%, Black wins 43.8%. That's a solid but not overwhelming conversion rate for White, especially given the +1.06 evaluation. Why the gap? Because Black's position, while worse, is hard for White to crack if you know the defensive ideas. The most popular move 6.c3 sees White score 53.7%, while the sharpest try 6.d5 (230 games) boosts White's score to 55.2% — more dangerous for you. On the other hand, 6.dxc5 (194 games) is surprisingly bad for White, scoring only 45.9%. If White takes on c5, you recapture with ...bxc5, opening the b-file and giving Black active play. That's a bright spot in an otherwise tough opening — know your replies to dxc5 and you can equalise your winning chances.
Results across 1,108 Lichess games
| Most-played continuation | Games | White wins |
|---|---|---|
| c3 | 402 | 53.7% |
| d5 | 230 | 55.2% |
| dxc5 | 194 | 45.9% |
| Be3 | 142 | 52.8% |
| O-O | 58 | 50.0% |
| e5 | 47 | 53.2% |
Frequently asked questions
Is the Modern Defense: Mongredien Defense playable for Black?
Yes, but it's tough. Stockfish evaluates the position at +1.06, meaning White is clearly better. However, Black still wins 43.8% of games at this level, and many of White's popular replies — especially 6.dxc5 — score poorly (45.9% for White). If you know the setup with ...Ba6 and avoid passive play, you can survive into a playable middlegame.
What is White's best move against the Mongredien Defense with Nf3 Bd3?
The engine's top choice is 6.c3, supporting the d4 pawn and preparing to meet ...Ba6 with O-O. It's the most common move in the database (402 games) and gives White a 53.7% score. The idea is simple: keep the centre solid, trade bishops on White's terms, and maintain the space advantage.
How should Black respond to 6.c3 in this line?
The engine recommends 6...Ba6 immediately, challenging White's Bd3. After 7.O-O Bxd3 8.Qxd3, you've traded off your potentially bad bishop. From there, play ...d6, ...Nd7, and aim for ...e6 or ...Nf6. The position remains better for White, but it's a standard Modern Defense struggle with clear plans for both sides.
What are the biggest mistakes White can make here?
White has two notable inaccuracies: 6.O-O (loses about 0.5 pawns) and 6.e5 (loses about 0.8 pawns). After O-O, Black should play ...cxd4 followed by ...Ba6 to trade bishops. After e5, Black can challenge the centre with ...d6 or develop quickly with ...Nh6. White's score after O-O drops to exactly 50.0%, so it's your best chance to level the game.