Our concern is with what Gu Li should have done, which means unwinding move 238 and replacing it with the sequence shown below:
By playing this way, White relies on the fact that, after White 9, taking back the ko at 3, Black no longer has any good ko threats. Bearing in mind that Black has to give 8 points komi under Ing rules, White will emerge slightly ahead from any compromise that lets both sides live, and play would be effectively over. Black's only sensible choice now, therefore, is to connect at A and try to keep the kos active. But this is the crux. Qiu Jun was convinced it was then a triple ko, and was baffled when he asked Wang Lei after the game to confirm that and Wang pooh-poohed it. When Wang was told later that Qiu was still maintaining there was a triple ko, he became vague (maybe only politely so) and referred Zhang to ghostbuster Gu Li.
The next diagram shows where Gu Li went wrong. He believed he now had to connect a ko at 11 (or A), but then of course he loses the capturing race as shown, even though it is a ko - Black will ignore any ko threat. This is also part of what Qiu Jun saw.
