Opening Leak Lab

English Opening

A10 1. c4

Black scores 48.8% here across 3,717 club games — but the 6.3% who answer d5 score 44.2%, 5 points worse.

What Black actually plays here

Across 3,717 games from a Lichess-derived book of club play, Black scores 48.8% in this position. These are the replies people choose, and how each one works out.

ReplyGamesShare Black scoresVerdict
e5 1,429 38.4% 46.7% holds up
Nf6 601 16.2% 52.9% holds up
c5 458 12.3% 52.2% holds up
e6 346 9.3% 53.2% holds up
d5 234 6.3% 44.2% below the line
g6 195 5.2% 50.0% holds up
c6 147 4.0% 42.5% below the line
d6 89 2.4% 47.2% holds up
b6 74 2.0% 51.4% holds up
f5 61 1.6% 50.8% holds up
Nc6 46 1.2% 37.0% 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.

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