Explanation
Open the explanation (shows the answer)
The answer is a5. With best play to the end: ±0 (a draw).
Best line: a5 f7 g1 f1 e8 h1 b2 f8 g8 h8
Other moves
| Move | Result | Why |
|---|---|---|
| a7 | -8 (a loss by 8) | The opponent's best answer is h8 (then a5 h7 f7). |
| f1 | -10 (a loss by 10) | Openness: 2 for this move (flips 2), 0 for a5 (flips 2). The opponent's best answer is f8 (then a5 h8 f7). |
| b2 | -16 (a loss by 16) | The opponent's best answer is h8 (then f7 h7 f8). |
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.