Explanation
Open the explanation (shows the answer)
The answer is e1. With best play to the end: +4 (a win by 4).
Best line: e1 d1 b1 e2 f2 g2 h1 c7 pass f1
Other moves
| Move | Result | Why |
|---|---|---|
| f2 | -8 (a loss by 8) | The opponent's best answer is e1 (then d1 b1 e2). |
| e2 | -16 (a loss by 16) | Openness: 4 for this move (flips 8), 2 for e1 (flips 2). The opponent's best answer is f2 (then f1 e1 d1). |
| d1 | -18 (a loss by 18) | The opponent's best answer is e1 (then e2 f1 f2). |
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.