Explanation
Open the explanation (shows the answer)
The answer is e1. With best play to the end: +14 (a win by 14).
Best line: e1 g7 a3 a2 a1 a4 a6 b2 a8 b7
Other moves
| Move | Result | Why |
|---|---|---|
| a3 | -14 (a loss by 14) | Opponent's moves: 7 after this move, 4 after e1. Openness: 3 for this move (flips 2), 0 for e1 (flips 4). The opponent's best answer is e1 (then a6 a1 a4). |
| a6 | -16 (a loss by 16) | Opponent's moves: 6 after this move, 4 after e1. Openness: 2 for this move (flips 4), 0 for e1 (flips 4). The opponent's best answer is e1 (then a8 a1 a3). |
| a4 | -18 (a loss by 18) | Opponent's moves: 8 after this move, 4 after e1. Openness: 4 for this move (flips 5), 0 for e1 (flips 4). The opponent's best answer is e1 (then a6 a1 a8). |
| a2 | -20 (a loss by 20) | Opponent's moves: 6 after this move, 4 after e1. Openness: 3 for this move (flips 2), 0 for e1 (flips 4). The opponent's best answer is e1 (then b2 h7 h8). |
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.