Problem diagram.
White plays.

Source:
American Go Journal, Vol. 20, No. 3, Aug 1986, p. 29
Keshi and Uchikomi, Kaoru Iwamoto 9 dan

Solution follows    (or click here to download SGF)

Failure.
White 1 is not good. Black 2 is the proper answer. Now White has no follow up against the Black corner. Moreover, White is now the one who is attackable.

Correct.
White 1 is the vital point for attacking the corner. Black 2 is the correct response for Black to attack the side group. Although through Black 6 this exchange is not quite satisfactory for either side.

Black variation.
If Black protects the corner with 2, then through 5, White completes his formation, while Black still has to worry about the danger of White A.

Black variation.
If Black tries 2 here, through White 7 shows the correct move order. After Black 10, White is a little overconcentrated on the right, but White's upper stone may have some aji.

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