Explanation
Open the explanation (shows the answer)
The answer is b5. With best play to the end: ±0 (a draw).
Best line: b5 a4 g1 e1 a7 c2 a2 b2 a1 a5
Other moves
| Move | Result | Why |
|---|---|---|
| g1 | -6 (a loss by 6) | The opponent's best answer is e1 (then b5 a7 c2). |
| e1 | -12 (a loss by 12) | The opponent's best answer is g1 (then b5 a7 a5). |
| c2 | -16 (a loss by 16) | The opponent's best answer is a3 (then g1 a7 b2). |
About these puzzles
Each position comes from a real game. The engine solved it to the end (perfect play by both sides) and only positions with a single best move, clearly better than the second-best move, were kept. "Best play wins by N" is the final disc margin when both sides play perfectly.
If you play a different move, you see the final margin your move leads to with perfect play afterwards, and how much it gave up. Results are stored only in this browser.
To be graded during a full game, go to the Reversi dojo.