( 983)

(Referenced by 292)

Let us assume that Black did not play the central throw-in at .

White would not have captured at , and thereafter filled-in at , but only connected her groups at .

Both groups gained a shared liberty. White's centre group has six liberties now (2 * w, 4 * c), Black's group in the upper right has eight liberties (4 * c, 3 * b, k).

The Punishment Semeai Liberty Level is seven, so White captured the ko a bit too early.

We added , and , for mutual adjustment of the liberty count. As usual with the main line with larger Black eye, White has five liberties, and Black has seven liberties.

Please note that we cannot use a shared liberty like for this adjustment, instead. With only six liberties for his top right group left, Black would be too far below the Punishment Semeai Liberty Level. In principle, Black has lost his flexibility to choose between the occupation of an outside White liberty, or a shared one. This will cost him one additional ko-threat for compensation, as we will see.

:
Black will use the "usual" atari in the hanezeki as a ko-threat, to avoid connecting the hanezeki's tail too early.

Ko:

:
With his move , Black cannot use the atari of as a ko-threat, because White's centre group has four liberties left. He needs an external ko-threat, instead.

Ko: ;

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But now, there is no Black outside liberty left that White could occupy. Therefore, she is able to pre-empt Black's ko-threat on the upper edge with her move at . This implies that Black needs a second external ko-threat for his move .

:
Compared to the original main line sequence, with Black's throw-in in the centre, Black is worse off here. Black should have played the kikashi of , , in time.