Cave Problem/Solution

Solution: White resigns.  

Namii: White resigns. I will show the reason later.

Herman:
Black has 78 points on the board, plus 8 prisoners, for 86
White has 67 points on the board, plus 13 prisoners, plus 6.5 komi, for 86.5
So why should white resign?
The prisoner count is off, by the way. Under Chinese rules, black is ahead by 4.5 points (2.25 zi)

Namii: Ah, I forgot to imply Japanese rules were used. Ok, I'll show the solution now.

Herman: Actually, you did. By giving the prisoner counts, you're implying Japanese rules, because there are no prisoners under Chinese rules. I was just remarking that the prisoner count is strange, because Chinese and Japanese rules should give the same result or a one point different result, but here the difference is four points (So I assume you fiddled with the prisoner count to make the result more exciting?) :-)

Namii: You are correct. In the real game, white had 3 less captures and black won by 2.5 points. Both players also left the cut alone.

Continuation. at  

Herman: What if at ?

Namii: Very interesting... I had not seen this move. I will put another diagram at the bottom.

Continuation. at  

Namii: So white had to protect, and doing so would lose the game by 0.5 points. So the elegant way is to resign. :-)

Herman: Elegant? Yes. Smart? Maybe not. White should pass, maybe black missed this sequence :-)

Namii: You are all so boring... (You are not the only one who said "white should push his luck" etc) I think the resignation is beautiful and would at least leave the spectators very puzzled.

Herman: Oh, I agree it's beautiful (As I said: "Elegant? Yes."), but if this were a tournament game, it'd be something of a shame if your opponent was as puzzled as the spectators :-)

gnostic?: If black just filled the last dame, and white is already ahead, white can just defend. Defending doesn't cost anything in Chinese rules aside from the opportunity cost of not being able to play something that actually gains points (i.e. filling a dame). Of course, if in the actual game white was behind by 2.5 points, and there were no dame and no tesuji available for white, just defending and counting up the game wouldn't be so bad. He could always find out that his count had been off somehow. Stranger things have happened.

 

Namii: Your move was very sharp.. I didn't find a way to counter it for black. However, I found a new move. After the sequence up to white has no move. We should probably update the page, since the original solution was not really a solution... :( and it was such a beautiful live-inside, too.

Herman: at a here?
I agree it was a beautiful sequence, and I might well have fallen for it in a game, the original is such a natural looking move :-)

at a  

Namii: White faces damezumari. If white plays at a next, black will capture the big chunk of stones with b.

Herman: Ah, missed that!

Namii: Now that I look at it again, black can also just play all the ataris (b, W connects, , w connects) and then connect at a. My head is suddenly starting to feel dizzy.

Your move was very brilliant, though. It must have been some sort of a blind spot to me, because I didn't find it when I rechecked everything before posting it here. I guess we can leave the page as it is as the discussion is quite interesting.

Herman: Now that I think of it, this analysis in fact shows that blacks last move in the original problem diagram () was a terrible mistake. Black could have played this immediately. So if you remove that move and readjust the prisoner counts to their original values, this is suddenly a "black to play and win" problem :)

at  

Herman: Another option for white is this , but - work in that case

Pedro I think you guys are missing a big capture for white in the middle

 

Bill: And then:

 

Bill: If at 3, at 2.