Problem p178

한국어

within 3, 5 legal points

Black to play. Capture the marked white stones within 3 moves.

Stones to capture: C9, D9, B8, C8, D8, C7

Black to play.

Why this is the move

White has 5 possible answers. Every one of them is listed below with the way Black captures. These are search results, not written commentary.

  1. Black A8, White pass, Black B7, White pass, Black B9 (captures 6)
  2. Black A8, White A9, Black B9, White pass, Black B7 (captures 6)
  3. Black A8, White B9, Black B7, White pass, Black A9 (captures 7)
  4. Black A8, White A7, Black B7, White pass, Black B9 (captures 6)
  5. Black A8, White B7, Black A7, White pass, Black B9 (captures 7)

Black has 5 legal points here and exactly one of them captures. White answers the others as shown and survives.

  • Black A9, White survives even by passing.
  • Black B9, White survives even by passing.
  • Black A7, White survives even by passing.
  • Black B7, White answers at A9 and lives.