Explanation
Open the explanation (shows the answer)
The answer is c2. With best play to the end: +6 (a win by 6).
Best line: c2 d2 b3 b2 a1 b1 c1 pass e1 f1
Other moves
| Move | Result | Why |
|---|---|---|
| b3 | -4 (a loss by 4) | The opponent's best answer is c2 (then d2 c1 g1). |
| b2 | -4 (a loss by 4) | b2 is an X-square (diagonal to the corner a1). While the corner is empty it tends to give the corner away. After this move the opponent can play the corner a1. The opponent's best answer is b3 (then c2 d2 c1). |
| e1 | -8 (a loss by 8) | The opponent's best answer is b3 (then c1 c2 d2). |
| d2 | -10 (a loss by 10) | The opponent's best answer is c1 (then e1 f1 g1). |
| f1 | -14 (a loss by 14) | The opponent's best answer is g1 (then c2 b2 b3). |
| g1 | -14 (a loss by 14) | The opponent's best answer is c2 (then f1 d2 b3). |
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.