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Rat Defense: Harmonist: what to play after Bc4?
Best move
c5+0.20
By playing c5, you immediately challenge White's central control and prepare to develop your b8 to c6. This move creates a Sicilian-style structure that limits the effectiveness…
- Games played
- 137K
- To move
- Black
- Evaluation
- +0.20
- Depth
- 22
Game counts: Lichess opening book. Move ranking and evaluation: Stockfish. How this page is built
Why c5 is the best move
c5! — Excellent Choice!
✅ One of 4 top moves — you found a high-level response that most humans miss!
Why this move is excellent:
By playing c5, you immediately challenge White's central control and prepare to develop your b8 to c6. This move creates a Sicilian-style structure that limits the effectiveness of White's c4 and prepares a counter-strike on the queenside.
Multiple Valid Strategies
This position is unique because it offers four distinct ways to maintain equality, each catering to a different playstyle:
| Move | Eval | Style / Strategic Idea |
|---|---|---|
| c5 | +0.20 | Positional: Challenges the center and controls d4. |
| Nxe4 | +0.22 | Tactical: A temporary sacrifice to disrupt White's center. |
| Bg7 | +0.27 | Solid: The most natural human move, completing the fianchetto. |
| a5 | +0.34 | Prophylactic: Gains space and prevents White's queenside expansion. |
Different paths, same destination: While 72% of players instinctively choose the "safe" Bg7, your choice of c5 is objectively stronger according to the engine. You are choosing to fight for the center immediately rather than just finishing development.
Your Continuation
After c5:
Nf3 Nc6 d3 Bg7 O-O
What Made This Move Good
You correctly saw: That White's setup with f4 and e4 is aggressive but leaves gaps. By placing a pawn on c5, you ensure that White cannot easily blast open the center with d4 without allowing you favorable trades.
📚 Takeaway: When you have multiple "best" moves, it's a sign of a healthy position. You found the most ambitious one!
What else gets played here
Move choices from 137K games in the opening book, with the engine's evaluation of each.
| Move | Evaluation | Played | Games | White score |
|---|---|---|---|---|
| c5Engine pick | +0.20 | 0 | — | |
| Nxe4 | +0.22 | 0 | — | |
| Bg7 | +0.27 | 0 | — | |
| a5 | +0.34 | 0 | — | |
| c6 | +0.36 | 0 | — |
The line
More positions in the Rat Defense
- Best moveBd3Bishop f1 → d3Rat Defense: Small Center Defense7.93M games
- Best movec5Pawn c7 → c5Rat Defense: Harmonist3.85M games
- Best movec5Pawn c7 → c5Rat Defense: Harmonist1.44M games
- Best moveh3Pawn h2 → h3Rat Defense: Small Center Defense1.06M games
- Best movef4Pawn f2 → f4Rat Defense: Antal Defense933K games
- Best moveexf5Pawn e4 → f5Rat Defense: Balogh Defense587K games
Frequently asked questions
What is the best move for Black in the Rat Defense: Harmonist?
c5 (+0.20). By playing c5, you immediately challenge White's central control and prepare to develop your b8 to c6. This move creates a Sicilian-style structure that limits the effectiveness…
Why is c5 the best move here?
By playing c5, you immediately challenge White's central control and prepare to develop your b8 to c6. This move creates a Sicilian-style structure that limits the effectiveness of White's c4 and prepares a counter-strike on the queenside.
How often does this position occur?
This position has been reached 137K times in the opening book.