(;
SZ[19]
AB[cf][ce][cd][cc][cb][hc][ib][hd][jc][hf][gg][fg][ef][dh][eh][if][cg]
AW[df][dg][eg][ff][ge][gd][gc][dc][dd][de]
C[Michael Redmond's Kisei Bonus Tsumego (solution)
Black to play.  Both sides must find a clever move for optimal play.  The first move is relatively easy, as White lives easily if Black plays any other move.
Published in the January 17, 2014 edition of the American Go E-Journal.

This bonus tsumego is just one example of the material, including pro game commentaries, available to Member's Edition subscribers.  See http://www.usgo.org/join-aga-today for how you can sign-up today.

Michael Redmond 9P shares with the E-Journal some of his own tsumego compositions.  For these more challenging problems, dan players can test their reading speed and accuracy, while kyu players can play through the solutions to learn ideas and techniques.

Michael based this problem on a very similar position that arose around move 63 of the just completed 1st game of the Kisei championship match in Spain.]

(;B[ee]C[After this correct first move, White has a few variations that seem worth considering.]
(;W[db]C[Covering here is the correct move.]
(;B[eb]C[The tsuke is Black's correct move.]
(;W[fb]C[White's correct move.]
(;B[da]C[Black's correct move.]
(;W[ea]C[White's correct move.];B[fa]C[Black must take.];W[ec]
(;B[gb]C[This ko is the correct answer.])
(;B[ea]C[This mistake allows White to live unconditionally.];W[ga];B[ca];W[fe]C[Alive.]))
(;W[ec]C[This will die.];B[ea]
(;W[hb];B[ed];W[fc];B[ha]C[Dead.])
(;W[ed];B[gb]C[Dead.])))
(;B[ec]C[Mistake!];W[ea]C[Alive.]))
(;W[ec]C[This makes it easy for Black.];B[fb]C[Dead.])
(;W[da]C[This will die.];B[gb];W[fb];B[fa];W[fc];B[ea]C[Dead.]))
(;B[gb]C[This hane does not attack strongly enough.];W[fb];B[ea];W[eb]C[White already has enough space to live.])
(;B[fb]C[This is the shape move, but in the end it doesn't work.];W[gb]
(;B[fe]C[This will be another failure for Black.];W[gf];B[ga];W[ha];B[fa];W[hb];B[fc];W[fd];B[da];W[ed];B[ee];W[ea]C[White lives.]
)
(;B[ga];W[ha];B[fa]LB[fc:A][hb:B]C[White can play at either A or B to live.]
(;W[fc]C[This also makes life for White.];B[hb];W[eb];B[ia];W[ed]C[Alive.])
(;W[hb];B[fc]
(;W[fd]C[Black wishfully thinks that White will play here, and ...];B[da]C[... White dies.])
(;W[ea]C[White can win the semeai to live.]
(;B[fe];W[fd]C[Alive.])
(;B[ed];W[fd]C[Alive])
(;B[fd];W[fe]C[Alive])))))
(;B[da]C[This is not the correct answer, but White must be careful.]
(;W[eb]C[This is White's correct move, and White is now alive.]
(;B[ed];W[gb]C[Alive.])
(;B[gb];W[fb]C[White has enough eye space.]))
(;W[ea]C[Covering is a mistake for White.];B[fb]C[White will die now.];W[gb];B[fa]
(;W[eb];B[ed]C[Dead.])
(;W[ca];B[ed]
(;W[ec];B[ga]C[Dead.])
(;W[fc];B[ec]C[Dead.]))
(;W[fc];B[eb]C[Dead.]))
(;W[fb]LB[da:A][fb:B]C[Both Black A and White B were mistakes.  The end result will be the same ko as in the correct answer.];B[eb];W[ea];B[fa];W[ec];B[gb]C[Ko.  Although this shape is the same as the correct answer, this variation is not correct, as White had a chance to live unconditionally.])))
(;W[eb]C[This kosumi looks like a shape, but does not work.];B[fe]C[First Black makes the 3-stone nakade shape.];W[gf];B[db]C[This vital point reduces White to 1 eye.]
(;W[ec];B[fb];W[gb];B[ea]C[Dead.])
(;W[fc];B[gb];W[fb];B[ed]C[Dead.]))
(;W[ed]C[If White plays here, ...];B[eb]C[... Black will take the side eye space away to kill White.];W[fb];B[db];W[fe];B[fc]C[Dead.])
(;W[fb]C[This looks like good shape, but actually does not give White enough space to live.];B[db]
(;W[ec];B[eb]C[The vital point.];W[hb];B[ed];W[fc];B[ha]C[Dead.])
(;W[ed];B[eb];W[ec];B[gb]C[Dead.])))
(;B[eb]C[Any move like this, and...];W[ee]C[... White lives by capturing the one stone.])
)
