(Referenced by 503)

During the Nakade Sequence of Our Solution, KataGo suggested White giving atari on the outside, instead of an atari on Black's nakade stones.
KataGo's atari is typical for the genius of Inoue Dōsetsu Inseki, because it can be played successfully at only one single moment in time. This fact can be identified as the main reason why we (who checked an atari at several earlier, and later, moments) and everybody else overlooked it.
Black does not have any option to prevent White from gaining a territorial advantage of four points that she can realise by choosing the Capture Variation.

For White's move in Our Solution, KataGo suggested giving atari at Black's single stone below, instead of immediately giving atari at Black's nakade (with a move at ).

Please take notice that we inserted the Hanezeki Exchange - to Our 2015 Solution (played before the Crosscut Sequence), as found in 2017 to be the correct timing for these moves.

KataGo's findings will be shown at an equivalent moment in the course of Our Solution.
KataGo has several changes in the order of moves, because e.g. it does not have a solid understanding of what a "technical correct timing" of a forcing move is.

White is played just after the final moves of the Crosscut Sequence (, ).

Black to follow the usual course of the Nakade Sequence.
But Black is double atari here. White will capture Black's single stone with .

Black connects the tail.
Black is able to do so, because White's group at the top left has only four liberties left (). White needed five moves to take Black's connected tail-group off the board, starting with the oki at .
Black's nakade-group has three liberties, and so is safe from becoming captured.

It will not benefit White to capture the tail, e.g. with here, in order to save her -group at the left.

As a matter of course, Black recaptures four White stones.

White now connects, where after Black defends against the cut at .
White tries to start a semeai with Black's nakade stones, but Black makes clear that White's three stones in the corner have one liberty too few.

White gives atari with .

Black to White follow the usual course of the Nakade Sequence.
Thereafter, Black leaves White helpless. She is unable to cut at , because Black will capture at .

White gives atari with .

Thereafter, White might connect her groups at the left with a move at , and later capture the tail with White , but Black will still win the game.
Black frustrates White's hopes for an eye in this area.
After White cut at , it is not necessary for Black to exchange Black for White . He can just capture White's single stone at the bottom with , so connecting his nakade stones.

White gives atari with .

Black plays the bamboo joint of that ends the discussion. The points of and are miai.

White gives atari with .

Black simply captures White's two stones at the left edge, connecting his nakade stones out.

White gives atari with , after the completion of the Nakade Sequence (, ). However, White's move contains only a single threat, this is to capture at .

Black simply captures at .

In the Capture Variation, Black's -group will be taken off the board.
Black's territory in the lower left is reduced by one point (), so

Black wins by 4 points.

White lost one liberty in the Main Semeai (), due to her atari. Black, however, will not use the just won liberty for also reducing White's territory in the upper right by one point, because White would also capture an additional prisoner in the Semeai Variation.

In the Semeai Variation, White's -group will be dead.
Again, Black lost that single point of territory at . But he gained an additional White prisoner at , as well as an additional point of territory, resulting in a net advantage of one point, so

Black wins by 4 points.