Petrov's Defense: Three Knights Game
C42 1. e4 e5 2. Nf3 Nf6 3. Nc3
Black scores 47.7% here across 4,075 club games — but the 0.7% who answer Qe7 score 44.6%, 3 points worse.
What Black actually plays here
Across 4,075 games from a Lichess-derived book of club play, Black scores 47.7% in this position. These are the replies people choose, and how each one works out.
| Reply | Games | Share | Black scores | Verdict |
|---|---|---|---|---|
| Nc6 | 1,914 | 47.0% | 46.7% | holds up |
| Bc5 | 868 | 21.3% | 47.3% | holds up |
| Bb4 | 517 | 12.7% | 53.0% | holds up |
| d6 | 408 | 10.0% | 48.5% | holds up |
| d5 | 146 | 3.6% | 46.6% | holds up |
| c6 | 65 | 1.6% | 47.7% | holds up |
| Bd6 | 43 | 1.1% | 46.5% | holds up |
| Qe7 | 28 | 0.7% | 44.6% | below the line |
"Below the line" means the reply scores at least three points worse than the position does overall. Replies played fewer than 25 times are left out: the sample is too small to read.
Is this costing you anything?
A table of averages cannot tell you whether you go wrong here — only your own games can. Opening Leak Lab reads your Chess.com or Lichess archive, finds the decisions you repeat, and checks each one against this book and a bundled Stockfish.