Explanation
Open the explanation (shows the answer)
The answer is d7. With best play to the end: +8 (a win by 8).
Best line: d7 b8 c6 b6 c7 b7 a8 a6 a7 b5
Other moves
| Move | Result | Why |
|---|---|---|
| b4 | -2 (a loss by 2) | Opponent's moves: 6 after this move, 3 after d7. Openness: 3 for this move (flips 8), 0 for d7 (flips 3). The opponent's best answer is d7 (then c7 b6 c6). |
| c6 | -2 (a loss by 2) | Opponent's moves: 6 after this move, 3 after d7. Openness: 3 for this move (flips 8), 0 for d7 (flips 3). The opponent's best answer is c7 (then b8 d7 pass). |
| b5 | -14 (a loss by 14) | Opponent's moves: 6 after this move, 3 after d7. Openness: 3 for this move (flips 7), 0 for d7 (flips 3). The opponent's best answer is b4 (then d7 b8 pass). |
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.