Explanation
Open the explanation (shows the answer)
The answer is e7. With best play to the end: +6 (a win by 6).
Best line: e7 f8 e1 f1 h6 g7 b7 a8 b8 c1
Other moves
| Move | Result | Why |
|---|---|---|
| e1 | -4 (a loss by 4) | The opponent's best answer is e7 (then f1 a1 b7). |
| f1 | -8 (a loss by 8) | The opponent's best answer is e7 (then g7 h6 h8). |
| h6 | -10 (a loss by 10) | The opponent's best answer is e7 (then h8 a1 e1). |
| b8 | -20 (a loss by 20) | Openness: 2 for this move (flips 4), 0 for e7 (flips 3). The opponent's best answer is f8 (then f1 a8 g7). |
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.