Problem diagram.
White to invade the upper side.
Assume that Black does not have an extension down the right side.

Source:
American Go Journal, Vol. 19, No. 2, 1985, pp. 22-23
Keshi and Uchikomi, Kaoru Iwamoto 9 dan

Solution follows    (or click here to download SGF)

Too timid.
The erasure move of White 1 would be good if Black had an extension down the right side. But here, this play gives Black too easy of a time.

Not good.
Even if White could live after Black 4, Black would build adequate compensation in terms of outside influence.

Effective.
White 1 is a good invasion point. White 3 is an excellent move that threatens to move out to the right. If Black blocks that exit with 4, White connects out to the left through 9.

See the SGF for other variations.

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