Referenced by ( 1813)

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White's defensive move at the bottom terminates the basic sequence of forming the hanezeki in the lower right corner.

The hanezeki's tail has reached its minimum length of two stones, caused by the two shared liberties of the large hanezeki groups and in the corner.

In this chapter, we will refrain from playing Harry's Hasami-Tsuke Sequence in the upper right corner before my Guzumi .

We wanted to find out whether not having fixed the shape in the upper right corner would increase Black's flexibility when playing my Guzumi.

However, as we had to realise after the extensive analysis by KataGo, this is not really the case.

: ( G 1864)
KataGo favoured the lengthening of the hanezeki's tail, with my Guzumi being the runner-up in the ranking of the associated win rates.

Black's push at is always a valid alternative option and consequently will not be considered by us in the following.

If a Black move at was manually enforced, KataGo's self-play games thereafter (with komi = -1) ended in a draw (adjusted White + 2), even with a very large number of playouts.

In these self-play games, KataGo mistaskenly blocked the path of the hanezeki's tail with a move at immediately.
Obiously, the correct reply with was hidden behind KataGo's event horizon.

: ( G 1865)
KataGo favoured the lengthening of the hanezeki's tail again.

KataGo assigned my Guzumi a win rate of about 30% (in Analysis Mode; with komi = -1), apparently having realised that this move was a mistake.

: (G 1866)
KataGo favoured the peep at the bottom.

KataGo assigned my Guzumi a win rate of about 40% (in Analysis Mode; with komi = -1).

Contrary to the comparable position with Harry's Hasami-Tsuke Sequence already played, a Black move at the Guzumi Point will not affect the final score of the game.
However, the choice of my Guzumi will complicate the ensuing sequence unnecessarily.

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Please note that White's connection fixes the shape at the bottom - for the time being.

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From here on, KataGo favoured the move at the Guzumi Point, with the win rate of the respective lengthening of the hanezeki's tail being the runner-up in the in the ranking of the associated win rates, ...

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... with the exception of the final move in the left centre before the start of the Crosscut Sequence.

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Afterwards, KataGo again prefered my Guzumi to the moves of the Crosscut Sequence ...

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... with the exception of Black's final connection in the upper left corner.

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KataGo favoured the start of the Nakade Sequence with as a kikashi at the left edge of the board, ...

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... before shifting its preference to my Guzumi .

:( G 1867)
KataGo favoured my Guzumi.

As you will see below, continuing the Nakade Sequence with is a grave mistake, so this is the very last moment for playing my Guzumi.

: (85 1868)
KataGo played tenuki, in order to push into White's upper left corner from below.

There were also self-play games in which KataGo immediately played Harry's Hasami-Tsuke at .

However, KataGo tended to lose points unnecessarily, apparently miscalculation the effect of capturing Black's nakade too early.
With correct play, by contrast, the subvariation would be better for White, i.e. playing Harry's Hasami-Tsuke first was a Black mistake.

: ( A 1881)
KataGo chose the usual conclusion of Harry's Hasami-Tsuke Sequence.

However, playing the solid connection at , instead, would have been better for her. White would gain one point overall, compared to Black's best line of play below.

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The interrupted Nakade Sequence at the left edge continues.

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KataGo likes to insert this "time tesuji" move at the lower edge.

: ( A 1883)
KataGo favours the atari at here, which has also been suggested by Harry.
This might be some kind of desperate measure by Black.

However, it would have been better for him to follow the usual course of the game with connecting at , instead.

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KataGo starts one of its astonishing attacks inside Black's upper left corner.

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Another surprising move of KataGo at the left edge.

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It is best for Black to fill his potential false eye immediately.

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White captures Black's nakade, in order to get rid of any potential shortage of liberties of her stones above.

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A White kikashi in the upper left corner.

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KataGo seems to be fond of this wedge in the left centre.

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Black must give atari from the outside.

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Finally, White completes the Nakade Sequence.

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White connects to her allies at the top.

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Black sacrifices a second stone, in order to settle the shape at the top.

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Another AI-typical forcing move in the lower left corner.

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The time has come to occupy the Guzumi Point.

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Black answers with Michael Redmond's Kikashi in the Bamboo Joint.

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KataGo likes jumping back and forth on the board.

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White chooses the solid connection, so keeping Black down at the Punishment Semeai Liberty Level.

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Black must occupy one of White's liberties at the left.

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Finally, White captures Black's two stones at the upper edge.

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White's previous move was gote, so Black takes the opportunity to play a large endgame move in the lower left corner.

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After having played several kikashi, White plays KataGo's Bad-Shape Move in the left centre.

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White continues her attack on Black's upper left corner.

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White continues with the Main Semeai.

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Black's surprising move in the left centre allows Black to connect at in sente.

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Black plays a kikashi of his own.

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The Main Semeai continues.

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Black is forced to capture White's single stone at the left edge, before occupying the upper liberties of White's left-hand group.

...

Black must not play any reduction.

After White's decision point, she will capture at , followed by and .
In the upper left corner, Black will have to capture at .

Capture Variation:

Compared to Our Solution (2021), ...

• Black cumulated loss in the upper left corner is six points.
• White captured two additional Black stones at the top, so gaining two points.
• White got an additional three points of territory in the Guzumi area.
• White got an additional point of territory in the right centre.
• White captured one Black stone in the left centre, so gaining one point.
• Black's cumulated gain in the lower left corner is five points.
• Black captured White's two stones in the lower left, so gaining four points.

In total, Black lost three points.

White + 2 => White + 5

Semeai Variation:

Compared to Our Solution (2021), ...

• Black cumulated loss in the upper left corner is six points.
• White captured two additional Black stones at the top, so gaining two points.
• White got an additional three points of territory in the Guzumi area.
• White got an additional point of territory in the right centre.
• White captured one Black stone in the left centre, so gaining one point.
• Black's cumulated gain in the lower left corner is five points.
• Black captured one White stone less in the lower left, so losing two points.
• White captured two Black stones less in the upper right, so losing four points.
• Black destroyed one point of White's territory in the upper right corner.

In total, Black lost four points.

Black + 4 => Jigo