Could someone please tell me if this problem has two valid solutions? This is problem number 135 from 1001 Life-and-Death problems. The problem is "Black to live" in one move. The only answer given is to play at F2 (variation 1), but playing at E1 (variation 2) seems to work also, even though it's not listed as an alternative answer. Could someone please clarify this for me?


Please see below post by jts:

I think this is the link you want

Sorry, could someone help out with getting this problem on here, too?

Thanks JTS!! I don't know why I wasn't able to get the file to show up.

The problem with your throw-in suggestion is

But if white plays tenuki, then it seems like anything black plays there would lead to the death of the group. So black would have no reason to play there it would seem.

Exactly - so Be1 doesn't work.

Okay, so my understanding of the situation is this:

If white plays a throw in after black blocks on the outside, then black can live. But if white plays tenuki, then any play inside the group will lead to the death of his group, thereby giving black no reason to play there. So, if this is the case, can black really be considered dead? This sounds almost like a seki-type situation, but not quite.

It's not a seki since w can approach from the outside and kill.

Okay, I finally got it!! White will eventually connect his A2 stone to the rest of the stones, and then thrust down to A1 and cover black's last outside liberty. Then it doesn't matter if black plays inside or not, since black will only have one liberty left inside if he doesn't play.

I don't know why I had so much trouble seeing that. Thanks, guys!!

We all had this before. It's one of the hardest things in go to "get" and why explaining seki vs non-seki can be hard. If w couldn't fill in that liberty, it could be one really huge seki.