BeginnersEndgameExercise5/Solution

White wins by 1 point  

takes away Black's potential eye in the center, setting up an eventual sente for White against Black's group. Black can do no better than to respond with and right away.

Variation 1  

is urgent, a 2-point reverse sente. (If , Black must respond at a to live.)

White still wins by 1.

Variation 2  

(Starting after .)

If at , kills.

White still wins by 1.

Jigo  

The sente, - , is tempting, but is aji keshi, securing 2 eyes for Black and reducing the value of White's plays on the right side and in the center.^[1]

is now best, but after the top and right sides are miai, to be shared equally. All White can get now is jigo.

( - is a losing sente, losing 1/32 point on average. Usually such a small error will cost nothing in the end, but this is a problem. ;-))