Referenced by ( 2022MainLine)

:
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.

This is also the moment when KataGo starts to seriously consider my Guzumi for Black again.

In the early days of our intensive analyses of the problem, the optimal moment for playing my Guzumi was for a long time an unresolved question. With our inadequate resources, we made an estimate of this at the time, ...
813

... which culminated in the perception that the "best" moment would probably be immediately before the start of the Crosscut-Sequence in the left centre.

Below we present KataGo's "opinion" on this complex of issues in detail.

:
KataGo likes to start the reduction of White's upper right corner immediately after the creation of the principle hanezeki has been completed, i.e. after the hanezeki's tail has reached its minimum length.

:
White blocks immediately.

:
Harry's Hasami-Tsuke follows.

:
White ends in gote.

///:

We will start the story of KataGo's evaluations with Black's moves in the upper right corner.

In the next chapter of our website you will find a comparable analysis of the position without previous Hasami-Tsuke Sequence.

( 1863)

:
KataGo favoured the move at the Guzumi Point, with the win rate of the push at only slightly lower.

This is the second moment when KataGo seriously considers playing my Guzumi.
However, it is a mistake to play my Guzumi with a length of the hanezeki's tail of only two stones, losing one point overall!

KataGo's assessment is not that reliable here.
It does not seem unlikely that the variation tree after this "too early" guzumi was not fully explored during KataGo's training, so that important influencing factors remained hidden behind KataGo's event horizon.

The subvariation for at is part of the next chapter ( 1864).

Below you will find a corresponding illustration for the case after Harry's Hasami-Tsuke Sequence.

:
White blocks immediately.

; :
KataGo continued with Harry's Hasami-Tsuke Sequence.

A Black move at the Guzumi Point was not considered.

:( G 1814)
KataGo favoured the lengthening of the hanezeki's tail.

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

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 mistakenly 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 1816)
KataGo favoured the lengthening of the hanezeki's tail again.

KataGo assigned my Guzumi a win rate of about 20% (in Analysis Mode; with komi = -1), apparently having realised that this move was a mistake.

If a Black move at was manually enforced, KataGo blocked the path of the hanezeki's tail with a move at immediately.

This made me aware of the change in the order of moves , , (most likely played much later), for the position two moves earlier, resulting in the correction of KataGo's line of play.

:
KataGo favoured the lengthening of the hanezeki's tail again, with the win rate of my Guzumi at only slightly lower.

Choosing my Guzumi at this point of the game leads to the variation of Our Solution (2021); please refer to ( 0009.htm#ü2021) for details.

: ( G 1817)
KataGo favoured the peep at the bottom.

KataGo assigned my Guzumi a win rate of about 25% (in Analysis Mode; with komi = -1), apparently having realised that this move was a mistake.

However, if a Black move at was manually enforced, KataGo needed a rather large number of playouts to successfully punish Black for his mistake in its self-play games thereafter.

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

:
From here on, KataGo favoured the move at the Guzumi Point, with the win rate of the respective lengthening of the hanezeki's tail only slightly lower.

:
From here on, KataGo favoured the lengthening of the hanezeki's tail, with the win rate of my Guzui only slightly lower.

Referenced by ( 2031)

:
KataGo wanted to play my Guzumi again just before the start of the Crosscut Sequence in the left centre.

: (G 1819)
KataGo favoured Black's extension in the left centre, so saving his cutting stone.

KataGo assigned my Guzumi a win rate of about 45% (in Analysis Mode; with komi = -1).

However, as you will see in the subvariation, choosing my Guzumi would complicate the game unnecessarily.

: (G 1821)
KataGo favoured Black's extension in the left centre, so saving his cutting stone.

KataGo assigned my Guzumi a win rate of about 30% (in Analysis Mode; with komi = -1).

However, as you will see in the subvariation, choosing my Guzumi would complicate the game unnecessarily.
This might be one reason for KataGo's great uncertainty about the playability of the Guzumi.

: (A 1822)
From here on, KataGo favoured the move at the Guzumi Point again, with the win rate of the respective continuation of the Nakade Sequence only slightly lower.

Please note that - with Harry's Hasami-Tsuke Sequence , already played - starting the creation of the nakade with a move at - as Fujisawa Hideyuki did in his classical solution - would be a grave mistake.

Referenced by ( 2022MainLine), ( 2032)

:( G 1823)
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.

:
White continues with the Nakade Sequence, as "usual".

:
KataGo's Atari.

:
Black chooses to answer with completing the nine-stone nakade at the left edge.

: (96 1824)
With a komi of -2, KataGo favours playing Yamada Shinji's Tsuke first.

Alternatively, White might immediately capture in the lower left with , not affecting the outcome of the game.

Referenced by ( 1869)

:
Black is forced to block immediately.

:
White occupies the Guzumi Point.

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

:
White answers with the solid connection, not losing any tempo in the Main Semeai.

:
Black defends his potential territory in the left centre.

:
White continues with KataGo's "immediate" crosscut in the upper left corner.

:
Black secures his territory in the lower left corner.

:
Black gives atari at White's two stones in the lower left.

; :
White does not connect her two stones, so keeping Black par with the Punishment Semeai Liberty Level.

:
The game follows a well-known path.

Referenced by ( 2031)

...

Black must not play any reduction.

Capture Variation:

Compared to Our Solution (2021), ...

• White destroyed four points of Black's territory in the upper left corner.
• Black did not capture White's single stone in this area, so losing one point.
• White got an additional two points of territory at the top.
• Black's cumulated gain in the lower left corner is five points.
• Black got an additional point of territory in the left centre.
• Black captured White's two stones in the lower left, so gaining four points.
• White got an additional point of territory in the right centre.
• White got an additional three points of territory in the Guzumi area.

In total, Black lost one point.

White + 2 => White + 3

Semeai Variation:

Compared to Our Solution (2021), ...

• White destroyed four points of Black's territory in the upper left corner.
• Black did not capture White's single stone in this area, so losing one point.
• White got an additional two points of territory at the top.
• Black's cumulated gain in the lower left corner is five points.
• White got an additional two points of territory in the Guzumi area.
• Black captured two White stones less at the left, so losing three points.
• White captured two Black stones less in the upper right, so losing two points.
• Black destroyed one point of White territory in the upper left corner.

In total, Black lost four points.

Black + 4 => Jigo