British Go Journal No. 56. June 1982. Page 17a.
It is possible to use the aji of captured stones to glean the odd extra point or two in the corner.
Diagram 1 |
Black is to play in Dia 1, many players hane at A only to be surprised by White responding at B, forcing C before adding D to take the necessary liberty from the black stones.
Diagram 2 ||
Diagram 3 |
Correct play for black is that shown in Dia 2, where Black's result is three points better. White can prevent Black's gain by playing 2 in Dia 3 but then he has to fight a ko for his entire corner.
Diagram 4 ||
Diagram 5 |
A similar position is shown in Dia 4. Correct play for White is as in Dia 5, where White 1 threatens to capture three black stones. Going back to Dia 4, because white A is sente the white hane at the marked stone is a play worth seven points, (assume for counting purposes that a player will always achieve his own sente moves) - seven and not six because if Black were to play this move, B will eventually be his sente forcing White to connect at C.
If Black wants to take away White's sente of A after the marked stone, then his best move locally is to play A himself. When the dame are filled Black will then have to go back and take a liberty from the three white stones. If you do the sum, you will find that a black play at A saves three points, thus white at the marked stone in Dia 4 is worth either seven points in gote or four in sente. Usually Black will prefer to let him have the seven in order to play elsewhere (on the basis that elsewhere is worth about seven points at the time when White should play at the marked stone.)