Source:
Problem diagram.
White to invade the upper right.
Akira Ishida & James Davies, Ishi Press
Solution follows
(or click here to download SGF)
Correct.
White 1 and 3 is a classic invasion sequence.
White holds A in reserve and threatens B to sandwich Black's
group against the marked White wall.
Continuation diagram.
After Black blocks at 4, White slides to 5.
Blocking again at 6 is the best that Black has.
White's forcing sequence through 15 is a success,
especially because White threatens to cut at A.
Black variation.
Trying to cut off White's group with 6 and 8 is bad.
White lives through 11, but now threatens White A, Black B, White C.
White's invasion has been a big success.
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