This is the game in which China’s Yu Zhiying and Mi Yuting won the gold meal in pair go by defeating Korea’s Kim Choi Jeong and Na Hyun. Click here for the sgf game file.
Black 37 (A in diagram 1, played by Choi) defends against a double peep at B, but lets white jump to C. Black is playing too safe. She should have capped at 1 in diagram 2. If white peeps, pushes, and cuts as shown in the diagram, black can give up two stones, after which white will be unable to reach the center. Then black can develop on a truly large scale by pressing white down on the lower side as shown (moves from 11 to 15 in diagram 2).
Black 43 (played by Na) was also too conservative. Black should have occupied white 52, the junction point of his framework on the right side and the white framework on the lower side. When white got to play 52, the Chinese pair had a territorial lead.
White 64 may have been an overextension. Black 65 immediately started to threaten white’s thin position. With 66, white began dancing around to protect the weak white stones in this area and the weak white group at the top. But white danced successfully. By the time white played 92, white’s weak stones and group were out of danger.
Black 111 (Na) may have been the decisive mistake. Before playing here, black could have made sente moves at 112 and 150. Instead, white was able to play 112 and 148-150 in sente, gaining approximately seven points.
Black’s last chance was to start the ko at 157, but black lacked the necessary ko threats. Black 159 was inadequate. White simply ended the ko with 160, gaining as much at the top as was lost in the bottom left corner. When black renewed the ko challenge at 183, white accepted by cutting at 184. When Yu took the ko with white 194, Na decided that black’s prospects were too poor to continue and offered to resign, and his partner agreed.
– Ranka, based on commentary by Michael Redmond 9p.