The first throw-in of Fujisawa Hideyuki 9p in the hanezeki seems to be such a "natural" move that it did not deserve the slightest professional comment.

We will analyse the specific peculiarities of this move, the most important of which is the reduction of White liberties in the temporary seki in the middle of the right side.

White could well have won the game by one point on the basis of this classical knowledge alone, if only she remembered her already well-known oki after capturing the hanezeki's tail!

Current analyses with KataGo led to the finding that White could have made a two-point gain by starting the endgame on the left side of the board "early".

Choosing Harry's Hasami-Tsuke Sequence for the reduction of White's upper left corner in due time would not only increase Black's flexibility in the game, but also affect the overall result, as KataGo discovered. White's additional gain would be reduced to only one point.

In conjunction with my Guzumi, the remaining disadvantage of not playing this first throw-in turns out to be the loss of one point in the Capture Variation.

Referenced by ( 2022MainLine)

Let's go back to the dawn of time ...

( 2022MainLine)
This is the position in the classical sequence by Fujisawa Hideyuki, when White's move at secured the connection of all her stones in the temporary seki in the middle of the right side.

: (A 2025)
Black's first throw-in at is mandatory in Fujisawa Hideyuki's classical line of play, as it is necessary to reduce the liberties of White's group in the temporary seki by one.

As a side effect, the sacrifice of this first throw-in stone will benefit Black by one point in the Capture Variation.

We will analyse in the subvariation below what happens if Black mistakenly forgoes this throw-in and continues immediately with the move at .

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White is forced to capture Black's just played stone.

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Black must solidly connect his stones at the right, so preventing White from occupying this point in sente (either for creating an eye for her group or for stealing Black's large group above a crucial outside liberty).

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White also connects, as she is in danger of becoming prey of a shortage of liberties after a Black throw-in at this point.

///:

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Later in the game, after the creation of Black's pyramid shape in White's eye at the left edge has come to its end, White occupies the Guzumi Point.

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Black pushes in the upper right, aiming at reducing White's corner territory.

Please note the entire reduction of White's upper right corner will not affect the relation of liberties in the Main Semeai.

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White blocks immediately.

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Black pushes once from the left.

Decades later, the world of amateurs will come up with Harry's Hasami-Tsuke of , instead.
Current analysis with KataGo (initially for a different reason) showed incidentally that the overall result of the game would be affected, turning Black's push into a one-point mistake.

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The reduction sequence ends with Black's descent to the upper edge.

Please note that Fujisawa Hideyuki's sequence for reducing White's upper right corner ends in gote for Black. Therefore, it cannot be played earlier in the game.

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To simplify the position for the forthcoming analysis of the relation of liberties, we exchange some Black and White moves.

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White has to end this procedure in gote, of course.

Please note that White will answer Black's atari at with in the Capture Variation (after White's hanezeki group has been taken off the board), while White has the benefitical kikashi of , in the Semeai Variation.

Liberties (in the marked area):

• Black has ten direct liberties .
• White has two direct liberties .
• Both sides share one liberty .

In total, Black has a surplus of eight liberties in the marked area.

Please note that both sides will have to occupy the shared liberty in the temporary seki last.

Consequences:

• Black will survive the Punishment Semeai.

Let's try to find out what KataGo thinks about this matter ...

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KataGo also starts with the occupation of the Guzumi Point.

Please note that KataGo will have exchanged for in the temporary seki much earlier in the game, and not let it unplayed before White's decision point, as Fujisawa Hideyuki did in his classical solution.

: ( 96 2025a)
After the exchange of for , we manually enforced Fujisawa Hideyuki's push from the left.

KataGo favours Harry's Hasami-Tsuke , of course.

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Black's descent to the upper edge terminates the reduction sequence.

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As a matter of course, KataGo favoured the continuation with Yamada Shinji's Tsuke in the upper left corner.

We manually enforced Fujisawa Hideyuki's Atari .

Starting the endgame on the left side of the board with Fujisawa Hideyuki's Atari "late" after the dissolving of the hanezeki (as in the classical line of play) would be a mistake, losing one point overall.

For further details, please refer to section "Jérôme Hubert's Correction of the Mutual Occupation of Opponent's Liberties" ( 2041c).

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White erases one of her remaining weaknesses in the encirclement of her upper right corner.

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Black is par with the Punishment Semeai Liberty Level, so he has to follow White with the Main Semeai.

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White starts the reduction of Black's lower left corner.

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Black defends his lower left corner to the left so avoiding unnecessary complications in the lower left corner.

White's previous move was played outside the Main Semeai Area, so Black gained one tempo in the Main Semeai.

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White continues with the hane at the upper left edge.

: ( 114 2025b)
For better comparison with the classical line of play, we manually enforced White's solid connection at , but which is a mistake, according to KataGo.

KataGo favoured immediately capturing Black's single stone at the upper edge with , instead, which will benefit White by one point overall.

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Black follows a well-known path.

: (A 2025c)
White takes further profit at the top, at the cost of losing another tempo in the Main Semeai.

White could also attach at in the upper left centre for reaching the same result overall. However, she would be worse in the Semeai Variation, as Black would not invest additional stones in the Main Semeai Area.

However, the subvariation will allow us a simple comparison with the historical line of play, in which the endgame on the left was started only after the resolving of the hanezeki.

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Black is able to exploit White's remaining weakness in the Guzumi Area, destroying several points of White's potential territory there in return.

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Black is back at par with the Punishment Semeai Liberty Level, and so has to continue with occupying White's liberties at the left.

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Sooner or later, White will have to fill the ko-shape at the upper right edge.

It would make no sense for Black to start a ko-fight with an own move at , since White will not give him any opportunity to continue capturing with .

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A surprising atari by KataGo.

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White loses one point in the Semeai Variation through this connection.

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Black is forced to take White's group in the temporary seki a liberty, to avoid an atari at his own group below.

Had KataGo not played its kikashi, the results of the two Main Variations would have swapped places.

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The Main Semeai continues.

Black must not play any reduction.

Capture Variation:

Compared to Our Solution (2015 / 2017), ...

• White's cumulated gain in the upper left corner and at the top is two points.
• White got an additional four points of territory in the upper right corner.
• White's cumulated gain in the hanezeki is one point.

In total, Black lost seven points.

Black + 5 => White + 2

Semeai Variation:

Compared to Our Solution (2015 / 2017), ...

• White's cumulated gain in the upper left corner and at the top is two points.
• White got an additional three points of territory in the upper right corner.
• White captured one Black stone less in the upper right, so losing two points.
• White's cumulated gain in the hanezeki is one point.

In total, Black lost four points.

Black + 3 => White + 1

Let's go back again to the dawn of time ...

VAR

: ( 2025)
Black connects his stones without having played any throw-in before.

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White connects at the lower cutting point, preventing a later Black throw-in at this point.

Please note that Black will not play the upper throw-in at later, as White's reply would cost his large group above a liberty.

For an analysis of White's connection at , please refer to the history of our research ...
72

Please also note that we limit ourselves here in this section to the classical line of play - with a later exception regarding the reduction of the upper right White corner for comparison purposes.

///:

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Later in the game, after the creation of Black's pyramid shape in White's eye at the left edge has come to its end, White occupies the Guzumi Point.

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Black pushes in the upper right, aiming at reducing White's corner territory.

Please note that not reducing White's upper right corner would not increase Black's liberties in the Main Semeai.

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White blocks immediately.

: ( 92 2025)
Black pushes once from the left as usual.

Decades later, the world of amateurs will come up with Harry's Hasami-Tsuke of , instead, which at least helps avert disaster. Provided this option is drawn much earlier in the game, which is possible because Harry's Hasami-Tsuke Sequence ends in sente for Black.

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Thereafter, he descends to the upper edge.

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White must play the last move here, in order to balance the number of played stones.

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To simplify the position for the forthcoming analysis of the relation of liberties, we exchange some Black and White moves.

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White has to end this procedure in gote, of course.

Please remember that White still has the kikashi of , at her disposal, to be utilised in the Semeai Variation.

Liberties (in the marked area):

• Black has ten direct liberties .
• White has three direct liberties (2x + ).
• Both sides share one liberty .

In total, Black has a surplus of seven liberties in the marked area.

Please note that both sides will have to occupy the shared liberty in the temporary seki last.

Consequences:

White has gained a liberty in the temporary seki by Black's abandonment of Fujisawa Hideyuki's First Throw-in.

White will win the game by a very large margin.

2025

Let's enter the world of amateurs and apply the knowledge gained there a few decades later ...

( 2025)
We already know from the previous section that Harry's here already played Hasami-Tsuke Sequence (, ) includes the option to sacrifice one or even both of the played stones again - in exchange for Main Semeai Liberties.
Consequently, we can expect the outcome of the game to be countable again.

For further details, please refer to section "Harry's Hasami-Tsuke Sequence" ( 2024)

( 2025)
We will show below that it would be a mistake to play Harry's Hasami-Tsuke only now, after the creation of the nakade at the left edge of the board.

(G 2025)
At the end of this section, we will discuss the application of Our Solution (2015 / 2017), where Black, but not White, occupied the Guzumi Point.

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To simplify the position for the forthcoming analysis of the relation of liberties, we exchange some Black and White moves.

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Please remember that Black has decided not to play any throw-in.

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White has to end this procedure in gote, of course.

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White has occupied the Guzumi Point, so Black tries his best with Michael Redmond's Kikashi in the Bamboo Joint.

: (A 2025d)
White will answer with the atari.

Choosing the solid connection of , instead, will be mistaken here.

Liberties (in the marked area):

• Black has ten direct liberties + 1 approach-move liberty = eleven effective liberties in total.
• White has three direct liberties .
• Both sides share one liberty .

In total, Black has a surplus of eight liberties in the marked area.

Consequences:

• Black must not connect any of his hasami-tsuke stones.
• Black will be able to play at e.g. in the right centre, as White must capture around the upper edge first.

Territory (in the Capture Variation):

Compared to Fujisawa Hideyuki's solution, ...

• White's cumulated gain at the upper edge is three points.
• Black destroyed one point of White's territory in the right centre.
• White did not capture Black's throw-in stone in the hanezeki, so losing one point.
• Black captured one White stone less in the hanezeki, so losing two points.

In total, Black lost three points.

White + 3 => White + 6

Territory (in the Semeai Variation):

Compared to Fujisawa Hideyuki's solution, ...

• Black's cumulated gain at the upper edge is one point.
• White did not capture Black's throw-in stone in the hanezeki, and did not get one point of territory there, so losing two points.

In total, Black gained three points.

Black + 4 => Black + 7

2025

( 2025)
VAR

: ( 2025)
Black plays Harry's Hasami-Tsuke much too late.

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White follows a well-known path.

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But not for very long!
Here, White chooses the solid connection of , instead of blocking the corner with .

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To simplify the position for the forthcoming analysis of the relation of liberties, we exchange some Black and White moves.

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Please remember that Black has decided not to play any throw-in.

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White has to end this procedure in gote, of course.

Liberties (in the marked area):

• Black has nine direct liberties + 1 approach-move liberty = ten effective liberties in total.
• White has three direct liberties .
• Both sides share one liberty .

In total, Black has a surplus of seven liberties in the marked area.

Consequences:

• White will choose, and win, the Punishment Semeai.

White will win the game by a very large margin.

Liberties (contd.):

Please note that connecting any of the hasami-tsuke stones will not make a difference.

• Black has nine direct liberties + 1 approach-move liberty = ten effective liberties in total.
• White has three direct liberties .
• Both sides share one liberty .

In total, Black has a surplus of seven liberties in the marked area, the same as above.

Consequences:

• White will choose, and win, the Punishment Semeai.

White will win the game by a very large margin.

Liberties (contd.):

Please note that connecting any of the hasami-tsuke stones will not make a difference.

• Black has ten direct liberties .
• White has three direct liberties .
• Both sides share one liberty .

In total, Black has a surplus of seven liberties in the marked area, the same as above.

Consequences:

• White will choose, and win, the Punishment Semeai.

White will win the game by a very large margin.

2025

In the world of amateurs, Harry's Hasami-Tsuke Sequence usually appears in conjunction with my Guzumi ...

: ( 2025)
In Our Solution (2015 / 2017), Black pushes into White's upper right corner just before the start of the Crosscut Sequence in the upper left centre.

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White blocks immediately.

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It follows Harry's Hasami-Tsuke Sequence.

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Thereafter, Black initiates the Guzumi Exchange.

///:

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Later in the game, after the creation of Black's pyramid shape in White's eye at the left edge has come to its end, we let White occupy another liberty of Black's large group in the upper right.
This serves the easy comparison with the variations shown above.

In reality, White would be forced to start the endgame at the left side of the board with Yamada Shinji's Tsuke "early", see the explanation further below.

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To simplify the position for the forthcoming analysis of the relation of liberties, we exchange some Black and White moves.

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White has to end this procedure in gote, of course.

Please remember that White has the kikashi of for in the Semeai Variation at her disposal.

Liberties (in the marked area):

• Black has eight direct liberties + four approach-move liberties = twelve effective liberties in total.
• White has three direct liberties .
• Both sides share one liberty .

In total, Black has a surplus of nine liberties in the marked area, one more than is needed to survive the Punishment Semeai.

Consequences:

• Black is able to connect both hasami-tsuke stones, at the cost of only one liberty effectively.
• White must start the endgame at the left side of the board "early" (due to Black's ninth surplus liberty that would Black enable to tenuki).

Liberties (contd.):

After the connection of his two hasami-tsuke stones, ...

• Black has eight direct liberties + three approach-move liberties = eleven effective liberties in total.
• White has three direct liberties .
• Both sides share one liberty .

In total, Black has a surplus of eight liberties in the marked area.

Consequences:

• Black will survive the Punishment Semeai.

Capture Variation:

Compared to Our Solution (2015 / 2017), ...

• White did not capture Black's two throw-in stones in the hanezeki, so losing two points.
• Black captured two White stones less in the hanezeki, so losing four points.

In total, Black lost two points.

Black + 5 => Black + 3

Please note that – compared to Our Solution (2015 / 2017) – the final scores of both MainVariations are identical here.

However, KataGo's later improvements provide White with an additional gain of seven points overall in the Capture Variation, which White would then win by four points.
This means that Black can in no way do without his two throw-in in the hanezeki, which will earn him two points in the Capture Variation.

Semeai Variation:

Compared to Our Solution (2015 / 2017), ...

• White did not capture two Black stones in the hanezeki, so losing two points.
• White capture one Black stone more in the right centre, so gaining two points.

In total, gains and losses compensate for each other.

Black + 3 => Black + 3

2025