(Referenced by 825)

: ( 127)
Now, Black tries this novel idea of Joachim Meinhardt, starting with the Crosscut Sequence. This idea, which leads to a more or less complicated ko, is explained in detail later ( 225). This variation here - after the additional exchange in the centre - is also shown in the theory chapter as FLAG 3 ( 1008).

:
After the hiki of , we here will apply its main line only to show that - in principle - there will result no difference, because White's earlier move at (= ) took both, the Black, and the White, groups a shared liberty.

: (89 128a)
KataGo keeps the ko at the right edge in reserve and plays at , instead.

, :
Similarly, KataGo does not play this exchange that commits White to Joachim's Ko-Semeai at the right edge (and prepares the construction of ko threats for it).
White's single -stone in the top left corner can become a surprisingly large burden for Black.

:
White pre-empts Black's larger eye in the centre, and simultaneously robs Black his inerasable ko-threat therein.

:
Black has no other option left but to connect the hanezeki's tail.

Occupying another shared liberty, with a move at , instead, leaves his group in the upper right with only seven liberties, so White would successfully follow the Punishment Semeai, starting with an own move at .

Ko:

:
White starts the ko on the right side, because her centre group has only four effective liberties left.

:
White has not played at yet, so this atari is no valid ko-threat. Black lacks external ko-threats on the rest of the board, thus his position is hopeless.

:
White simply connects the ko.

:
White is the decisive step faster, and wins the semeai.