( 988)

(Referenced by 142; 1008)

Now, we will transform the starting position to one with a smaller eye for Black's group. We will assume that neither nor have been played.

Instead, we assume the exchange of / in the centre. Black's group has a smaller eye now. The conditions concerning the liberty count are as with the larger eye, five liberties for White (2 * w, 3 * c), and seven liberties for Black (3 * c, 3 * b, k). However - due to the missing larger eye - Black was below the Punishment Semeai Liberty Level, even before White captured the ko. Therefore, we will take / off the board. Black has one ko-threat in the hanezeki.

:
Black uses the atari of in the hanezeki as a ko-threat, to avoid connecting the hanezeki's tail at a moment, when White's centre group still has five effective liberties (2 * w, 3 * c).

Ko: ; ; ; ; ;

:
Please note the precondition that White must not have any option to erase all of Black's forthcoming ko-threats with only one move.

:
Together with his larger eye, Black has lost his internal ko-threat, as well as the shared ko in the centre, so it should be evident that Black needs three external ko-threats to win the ko-fight now.

This result is two external ko-threat worse than with a larger eye, or with smaller eye, but with an additional, and shared, ko in the centre.