Nakayama Ladder Problem

Can black capture the seven stones at the bottom by playing a? (177 moves)  

This ladder problem, number 17 in the second edition of The Treasure Chest Enigma, was composed by Nakayama Noriyuki. The black stones spell out his name Nakayama in Kanji: 中山

The question is whether black can capture the seven white stones at the bottom in a ladder by playing a.

As this is a ladder problem, the solution contains relatively few branches. But since it is meant to be done all in your head, the problem is still quite hard. Nakayama showed a problem like this one to Takemiya once who looked at it for a few seconds(!) only and solved it.

• Attempts
• Solution