In game Lee ChangHo(W) vs Chen Yaoye(B) after black 171 white play J18, why white can't play G14? I count that semeai after G14 is good to white can anyone help me?
[sgf]
(;GM[1]FF[4]CA[UTF-8]ST[2]
RU[Japanese]SZ[19]KM[6.50]
PW[Lee Changho]PB[Chen Yaoye]WR[9d]BR[4d]DT[2005-05-18]EV[10th LG Cup]RE[B+Resign]
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;B[jb]LB[ib:A][gf:B])
[/sgf]
G14 does not work. I
G14 does not work. I discussed this with a 7-dan friend, who suggested that black can L19 atari when white G14. Then --
(1) If white connects, there would be another ko left at J19 when white has J18. Then whatever the semeai situation, black could win.
(2) If white ignores L19, black M18 already kills the whole upper-right corner. Then black would have about 30 points lead after the exchange.