Sicilian Defence, Open by rating
1.e4 c5 2.Nf3 d6 3.d4 cxd4 4.Nxd4
The Open Sicilian is the most played answer to 1.e4 at every level, and it punishes approximation more than any other opening here. After 4.Nxd4 the engine wants Nf6, and the rate at which players actually find it roughly doubles across the rating range.
How often each rating finds the engine move
47 percent at 1000 rising to 94 percent at 2200 on the early position, and 30 to 63 percent two plies later.
The position after 1.e4 c5 2.Nf3 d6 3.d4 cxd4 4.Nxd4
This is where the opening actually starts asking a question. 28 moves are legal; Stockfish scores every one of them at depth 20.
Stockfish plays Nf6 at -0.39. Its next two choices are Nc6 (-0.54) and Bd7 (-0.63).
| Rating | Most likely human move | Finds Nf6 | Cost in pawns |
|---|---|---|---|
| 1000 | Nf6-0.39 | 47% | same move |
| 1200 | Nf6-0.39 | 52% | same move |
| 1400 | Nf6-0.39 | 57% | same move |
| 1600 | Nf6-0.39 | 63% | same move |
| 1800 | Nf6-0.39 | 72% | same move |
| 2000 | Nf6-0.39 | 84% | same move |
| 2200 | Nf6-0.39 | 94% | same move |
Two plies deeper
Following the most popular human continuation at 1400: Nf6 (57%), then Nc3 (81%).
Stockfish plays a6 at -0.33. Its next two choices are Nc6 (-0.39) and Bd7 (-0.56).
| Rating | Most likely human move | Finds a6 | Cost in pawns |
|---|---|---|---|
| 1000 | a6-0.33 | 30% | same move |
| 1200 | a6-0.33 | 50% | same move |
| 1400 | a6-0.33 | 60% | same move |
| 1600 | a6-0.33 | 64% | same move |
| 1800 | a6-0.33 | 67% | same move |
| 2000 | a6-0.33 | 67% | same move |
| 2200 | a6-0.33 | 63% | same move |
See this for your own games
Chessdrive runs the same two engines on your phone. It shows the move you should have found at your rating, not just the move a 3500-rated engine would have played.
How these numbers were produced
Stockfish 18 by the Stockfish developers (see AUTHORS file) at depth 20, with MultiPV set to the exact legal move count of each position so no move is left unscored, and Maia3, chessformer, human move prediction, 5m (bundled with maia3-js, UofTCSSLab/Maia3-5M, about 5M parameters) for the human move distribution. Run on 2026-08-29 over 28 positions across 7 rating bands. Findability is Maia3's probability for Stockfish's top move; it is not a claim about win rate.