World Amateur Go Championship problem
Posted: Wed May 26, 2010 3:27 pm
The following position appeared behind the sign-in table on a demo board at the ongoing 31st World Amateur Go Championship. So I'm assuming that the problem is above my pay grade, but I've taken a shot at an analysis anyway. What am I missing?
[sgf-full](;
AB[ab][bb][cb][cc][bd][ce][df][ef][fe][fc][gc][hb]
AW[ba][ca][db][dc][cd][dd][de][fb]
C[Status?
From a demo board at the 31st World Amateur Go Championship in China.];
(;
W[cf]
C[Best?]
(;
B[bf]
C[Best?];
W[be];B[ae];W[bg];B[ce];W[cg]
C[White has a local ko threat.];
B[ac];W[be]
C[White takes the ko 1st. If White wins the ko, White destroys anything that Black has on the left side.]
)
(;
B[be]
C[Fails?];
W[bf];B[ac];W[ae];B[cg];W[bg];B[ch]
(;
W[bh]
C[Works?];
B[bi]
(;
W[bj]
C[Works?];
B[ci];W[ai];B[cj];W[bk];B[cl];W[bl];B[cm];W[bn];B[cn];W[bo];B[bm];W[am];B[cp];W[ck];B[dk];W[co];B[do];W[dn];B[em];W[dp];B[eo];W[cq]
)
(;
W[ci]
C[Fails];
B[di];W[cj];B[bj];W[bk];B[ck];W[dj];B[bl];W[dg];B[dh];W[eg];B[eh];W[fg];B[fh]
)
)
(;
W[bi]
C[White doesn't have time to jump.];
B[bh];W[ah];B[ag]
)
)
)
(;
W[be]
C[Inferior?];
B[cf]
(;
W[ad]
C[Better, because White has a local ko threat?]
(;
B[ac]
C[Best?];
W[bf]
C[Local ko threat];
B[bg]
C[If Black loses the ko, the left side is not open.]
)
(;
B[bc]
C[Fails?];
W[bf];B[bg];W[ae];B[ag];W[da];B[af];W[aa];B[ac];W[be]
(;
B[ae];W[ad];B[bc];W[bd];B[bb];W[fa]
)
(;
B[ad];W[ae];B[bc];W[bd]
)
)
)
(;
W[bf]
C[Slack? White wastes a ko threat.]
)
)
(;
W[bf]
C[Inferior?];
B[cf];W[be];B[bg]
C[Tranposes to the previous inferior line.]
)
)[/sgf-full]
[sgf-full](;
AB[ab][bb][cb][cc][bd][ce][df][ef][fe][fc][gc][hb]
AW[ba][ca][db][dc][cd][dd][de][fb]
C[Status?
From a demo board at the 31st World Amateur Go Championship in China.];
(;
W[cf]
C[Best?]
(;
B[bf]
C[Best?];
W[be];B[ae];W[bg];B[ce];W[cg]
C[White has a local ko threat.];
B[ac];W[be]
C[White takes the ko 1st. If White wins the ko, White destroys anything that Black has on the left side.]
)
(;
B[be]
C[Fails?];
W[bf];B[ac];W[ae];B[cg];W[bg];B[ch]
(;
W[bh]
C[Works?];
B[bi]
(;
W[bj]
C[Works?];
B[ci];W[ai];B[cj];W[bk];B[cl];W[bl];B[cm];W[bn];B[cn];W[bo];B[bm];W[am];B[cp];W[ck];B[dk];W[co];B[do];W[dn];B[em];W[dp];B[eo];W[cq]
)
(;
W[ci]
C[Fails];
B[di];W[cj];B[bj];W[bk];B[ck];W[dj];B[bl];W[dg];B[dh];W[eg];B[eh];W[fg];B[fh]
)
)
(;
W[bi]
C[White doesn't have time to jump.];
B[bh];W[ah];B[ag]
)
)
)
(;
W[be]
C[Inferior?];
B[cf]
(;
W[ad]
C[Better, because White has a local ko threat?]
(;
B[ac]
C[Best?];
W[bf]
C[Local ko threat];
B[bg]
C[If Black loses the ko, the left side is not open.]
)
(;
B[bc]
C[Fails?];
W[bf];B[bg];W[ae];B[ag];W[da];B[af];W[aa];B[ac];W[be]
(;
B[ae];W[ad];B[bc];W[bd];B[bb];W[fa]
)
(;
B[ad];W[ae];B[bc];W[bd]
)
)
)
(;
W[bf]
C[Slack? White wastes a ko threat.]
)
)
(;
W[bf]
C[Inferior?];
B[cf];W[be];B[bg]
C[Tranposes to the previous inferior line.]
)
)[/sgf-full]
at d19 pretty much doom white? Just a try before I head to bed