Chessy
How to Play the Modern Defense: Mongredien Defense (Be3) as Black
After 1.e4 g6 2.d4 Bg7 3.Nf3 b6 4.Be3, you have reached the Mongredien Defense line of the Modern Defense. The position looks quiet, but White already has a meaningful advantage: Stockfish rates it +1.03, a clear edge for White. That means you are clearly worse here as Black. Don't panic — the statistics show Black scores a respectable 46.7% from this exact position across nearly 27,000 games. The key is knowing how to respond to White's most common moves and steering toward positions where your bishops can fight back. Let the drill below show you how.
Play the Modern Defense: Mongredien Defense, with Nf3: Be3 against the engine
Free, no signup — you play black, the engine adapts to your level.
Now that you understand the position, test your skills against the interactive drill. Play the Black side and see if you can steer this slightly worse position,
Create a free account →The Problem You Face: White's Space and the Bishop on e3
White has built a classic centre with e4 and d4, while your early ...g6 and ...b6 have left you a step behind in development. The engine's +1.03 is not a trivial number — it reflects White's superior central control and active pieces. Your bishop on g7 is strong diagonally but for now it's blocked by your own d6 pawn. The white bishop on e3 is especially annoying: it supports White's centre and can jump into the attack if you castle kingside carelessly. The good news? Black scores almost as many wins (46.7%) as White (49.4%) in practice, so the position is playable if you know what to do. Draws are rare here at just 3.9%, meaning this line tends to produce decisive results — you are fighting for a win, not a draw.
The Engine's Idea: White Wants Qd2
At depth 16, Stockfish's top suggestion is Qd2. This is a flexible developing move: the queen steps off the d-file, connects the rooks, and prepares to castle queenside. The engine's full plan continues Qd2 Bb7 Nc3 Nf6 — White develops naturally, keeping the option of long castling open. If White plays Qd2, you should follow the engine line with ...Bb7 and ...Nf6, challenging the centre and completing your own development. Notice that White delays committing a bishop to d3 or c4, keeping the position flexible. In practice, Qd2 is only the fourth-most popular move (2,483 games), but it's the engine's choice for a reason.
What the Statistics Say About White's Options
With 26,969 games in the database, we have solid data on what White actually plays. Here is how the most popular moves perform for White, and what that means for you as Black: - Nc3 (7,370 games, White scores 50.8%): White's most common move. Develops the knight but doesn't pressure you immediately. A balanced result. - Bd3 (6,761 games, White scores 47.9%): White scores below 50% here — this is your best chance among the popular moves. The bishop on d3 can be a target after ...c5 or ...e5 breaks. - Bc4 (2,517 games, White scores 51.8%): The most dangerous-looking popular move. White aims at f7. Be careful with kingside castling. - c3 (1,889 games, White scores 46.2%): Another favourable option for you. White's c3 is passive and blocks the b1-knight's best square. - c4 (1,645 games, White scores 48.7%): White claims more space but weakens the d4-pawn. You can target it with ...Bb7 and ...Nf6. The takeaway: when White plays Bd3 or c3, you are statistically doing well. Stay alert against Bc4.
Your Typical Plan: Undermine the Centre and Activate Your Pieces
Regardless of White's choice, your general strategy in this position follows the same principles. First, develop your bishop to b7 — it will pressure White's centre, especially the d4 and e4 pawns. Second, bring your knight to f6, fighting for control of e4 and preparing to castle kingside. Third, look for pawn breaks: ...c5 challenges the d4 pawn, and ...e5 challenges the e4 pawn. If White castles queenside (common after Qd2), your kingside attack with ...h5-h4 can be potent. If White castles kingside, you can sometimes play ...d5 to open the centre. Remember, you are the one with the lasting advantage against you, so play solidly — avoid unnecessary pawn weaknesses and don't rush to attack until your pieces are developed.
Results across 26,969 Lichess games
| Most-played continuation | Games | White wins |
|---|---|---|
| Nc3 | 7,370 | 50.8% |
| Bd3 | 6,761 | 47.9% |
| Bc4 | 2,517 | 51.8% |
| Qd2 | 2,483 | 50.6% |
| c3 | 1,889 | 46.2% |
| c4 | 1,645 | 48.7% |
Frequently asked questions
Is the Mongredien Defense a good opening for Black?
The Mongredien Defense (1.e4 g6 2.d4 Bg7 3.Nf3 b6) is a perfectly playable but slightly risky line. The engine gives White a clear advantage of +1.03 after 4.Be3 d6, meaning you are worse from the start. However, Black wins 46.7% of games at club level, so it can be effective if you know the typical plans and your opponent isn't booked up.
What is White's best move against the Mongredien Defense?
According to Stockfish at depth 16, White's best move is Qd2, planning Qd2 Bb7 Nc3 Nf6. This flexible queen move prepares queenside castling and keeps all options open. In practice, White most often plays Nc3, which scores 50.8% for White — solid but not crushing.
How should Black respond to White's Bc4 in this line?
Bc4 is played in about 2,517 games and scores well for White at 51.8%. Black should be careful about kingside castling — the bishop on c4 eyes the f7 pawn. Your best response is to develop naturally with ...Bb7 and ...Nf6, then consider ...c5 to challenge the centre and trade off the d4 pawn. Avoid ...e5 too early, as it weakens the d5 square.
Should I castle kingside or queenside as Black here?
Kingside castling is the standard choice in this position. Your king is relatively safe on g8 behind the g6 pawn and the dark-squared bishop. Queenside castling is risky because you have advanced your b-pawn to b6, leaving the a7-c5 diagonal exposed. Stick to ...0-0 and then counterattack in the centre or on the kingside depending on where White castles.