Valkhiya: After E19, isn't E17 seki? And if seki is acceptable here, why are D18 or E17 not acceptable solutions as well? I don't see how the attacker gets any better than seki in either case.
caranthir: If D18, then E17 kills. If E17, then D18 kills. In either case, we cannot prevent the attacker from almost-filling the space with a bulky five nakade (attempt to do so would be self-atari). If there were any outside liberties, it would be a different story.
If D18, then E17 kills. If E17, then D18 kills. In either case, we cannot prevent the attacker from almost-filling the space with a bulky five nakade (attempt to do so would be self-atari). If there were any outside liberties, it would be a different story.