Probably safe to say that this is a problem which most people here have never encountered. It comes from a rare Ming Dynasty weiqi manual which only has words and no diagrams. Quite an interesting problem. You will need to look for the strongest line to find the right answer. Have fun.
(;GM[1]FF[4]AP[Drago:4.01]CA[UTF-8]SZ[19]AB[ra][pb][pc][qd][qe][qf][qg]AW[nb][qb][nc][qc][od][pd][pf][pg][ph][qh][sh][ri]PL[W]C[White to kill unconditionally])
Re: An interesting ancient tsumego
Posted: Fri Apr 08, 2011 4:37 am
by John Fairbairn
Aha! Nine Old Men is the clue. Relieved to see this old man can still remember some things.
Re: An interesting ancient tsumego
Posted: Sat Apr 09, 2011 2:43 am
by unkx80
I came across a problem that looks very similar to this problem. According to the commentary, the solution is intended to be unconditional kill, but subsequent research indicates that black can get a ko.
$$W Ko? $$ -------------- $$ . . . . . X . | $$ . O . X O . 3 | $$ . O . X O 1 2 | $$ . . O O X . . | $$ . . . . X . 4 | $$ . . . O X . . | $$ . . . O X . . | $$ . . . O O . O | $$ . . . . . O . |
[go]$$W Ko? $$ -------------- $$ . . . . . X . | $$ . O . X O . 3 | $$ . O . X O 1 2 | $$ . . O O X . . | $$ . . . . X . 4 | $$ . . . O X . . | $$ . . . O X . . | $$ . . . O O . O | $$ . . . . . O . |[/go]
Re: An interesting ancient tsumego
Posted: Sat Apr 09, 2011 6:31 am
by tchan001
It wouldn't be the first time I've heard of ancient problems having a solution as ko after subsequent research. I wouldn't be strong enough to show refutations anyways. I only have the main line from the ancient text.
Re: An interesting ancient tsumego
Posted: Sun Apr 10, 2011 5:19 pm
by cyclops
BTW, B4 under 1 doesn't work in unkx's diagram.
$$Wc $$ --------------+ $$ . . . 7 8 X . | $$ . O . X O 9 3 | $$ . O . X O 1 2 | $$ . . O O X 4 6 | $$ . . . . X . 5 | $$ . . . O X . . | $$ . . . O X . . | $$ . . . O O . O | $$ . . . . . O . | $$ . . . , . . . |
[go]$$Wc $$ --------------+ $$ . . . 7 8 X . | $$ . O . X O 9 3 | $$ . O . X O 1 2 | $$ . . O O X 4 6 | $$ . . . . X . 5 | $$ . . . O X . . | $$ . . . O X . . | $$ . . . O O . O | $$ . . . . . O . | $$ . . . , . . . |[/go]
Black won't get his second eye below 4 and 6.
$$Wc $$ --------------+ $$ . . . . 6 X . | $$ . O . X O . 3 | $$ . O . X O 1 . | $$ . . O O X 4 7 | $$ . . . . X . 5 | $$ . . . O X . . | $$ . . . O X . . | $$ . . . O O . O | $$ . . . . . O . | $$ . . . , . . . |
[go]$$Wc $$ --------------+ $$ . . . . 6 X . | $$ . O . X O . 3 | $$ . O . X O 1 . | $$ . . O O X 4 7 | $$ . . . . X . 5 | $$ . . . O X . . | $$ . . . O X . . | $$ . . . O O . O | $$ . . . . . O . | $$ . . . , . . . |[/go]