InvincibleTheGamesOfShusaku/Game 36 analyzed with KataGo

The 7th castle game by Shusaku is against Inoue Matsumoto Inseki. It's the first castle game where he takes White. Commentator is Miyamoto Naoki.

Moves 21 to 30  

In the top left Matsumoto avoids the complex variations of the taisha and then plays an ideal move with B23. Next however B27 is a mistake, according to KataGo. The pro also notices that A, KataGo's alternative, would have been better, even already at B25.

W30 is probably the reason why B27 wasn't so good. It's an obvious reduction point.

Moves 31 to 40  

W36 gets a lot of praise by Miyamoto. KataGo too likes the combo here but would first play A.

Moves 41 to 50  

From W44 to B49 the players play chicken and surround each other. White is the first to defend. The book analyzes thoroughly what happens if B47 breaks out with the top left group.

Instead of surrounding with B49, KataGo would defend the top at the vital point A. White's vital point in the top right is B but KataGo has a slight preference for moving out with C. White however plays the sharper W50.

Moves 51 to 60  

Matsumoto counterattacks at the vital point B51. KataGo agrees. When W52 continues, Black has another option for B53, says KataGo.

Cutting instead  

Black can cut at B1 instead of B53 in the game. Now White has a lot of work to do in the top left while dealing with aji like A.

Miyamoto discusses the cut in the book:

Miyamoto's diagram  

Miyamoto has W2 connecting here, leading to an escape to the center. KG finds this an acceptable variation but thinks Black can do better.

KataGo's sharp turn  

If B1 turns first before playing B3, White has a tough decision to make. W2 seems to end in disaster (playing out a couple of variations) so it might be better for White to play W4 immediately and sacrifice 3 stones. Still there's a lot of aji in the corner and Black might get sente in the top left.

Miyamoto's variation  

Miyamoto also discusses B1. He doesn't like the result up to W10, where White lives with miai of A and B.

KataGo sees many more variations and basicially prefers the cut for most of them.

Moves 61 to 70  

Black lets White off the hook in the game, allowing him to live inside while taking territory and sente for himself. When W70 takes sente to play the big point, Miyamoto calls the game extremely close. KataGo thinks Black still leads by 3,5 points.

Miyamoto calls White's settling at the top "brilliant". As we have seen, Black could have countered but decided to keep things peaceful. What's clear is that Shusaku created major complexity to test Matsumoto's strength to the fullest.

Moves 71 to 80  

Miyamoto calls the light reduction of B71 correct. Again KataGo finds a more aggressive move (see next diagram). B73 is "the only move" in the book but KataGo wants to continue in the center.

KataGo's counter  

KataGo finds this astute "half peep" aiming at the ko of A while simulteanously threatening to separate at B. For White to cover at A would be dame so he should fight again, in Black's sphere of influence.

B79 in the game is quite similar and White seems compelled to defend:

Moves 81 to 90  

After forcing with W90 in the previous figure and W92 here, W94 returns to defend. This keeps Black ahead. The endgame is near now and Black takes B85, allowing W86. Miyamoto questions if Black shouldn't have taken W86 for himself. KataGo has another idea:


W10 at B3. Next Black can play A and take territory while attacking. Black can now also look forward to some central territory.

Moves 91 to 100  

Both apply mutual damage but it's White who gradually reduces the gap this way.

Moves 101 to 110  

Miyamoto calls W2 "essential" to prevent Black's central territory. KataGo values the endgame diagonal at A at least on par.

However W10 is a mistake per KataGo's analysis.

Moves 111 to 120  

W14 and W18 force from the outside before living.

KataGo doesn't think W14 is forcing and suggests the following counter:

Countering at B115  

Rather than connecting, it cuts off White's lifeline to the bottom while reducing the corner. White can indeed push through as Miyamoto argues, so that if Black blocks at A, White can capture two cutting stones at B. But Black can throw these away! He can reinforce at B3 and the focus then lies on White's corner with moves like C and D which White can't have both.

In the game, Black is playing on neutral points while White takes the large point on the side as kikashi. This is a big difference.

Moves 121 to 130  

W22 and W24 reduce the center to an almost neutral area.

Moves 131 to 140  

B33 is a small loss and should have been at B39 but Black gets another chance.

Moves 141 to 150  

Finally, when B45 links up his stones without any profit, W46 takes a small lead, which Shusaku will convert into a 2 point victory.

There are many comments in the book about the endgame and we could spend more analysis on those with KataGo's view, but this is enough.


Miyamoto Sensei concludes that Matsumoto Inseki has made no mistakes but Shusaku played brilliantly, moving into the lead imperceptibly, the key moment being the skillful settling of his group in the top right.

KataGo indeed doesn't reveal any big point losing mistakes by Black but there are some points in the game where he could have counterattacked to maintain or regain the lead, most notably the cut at B53, which the book dismissed, and the clever play at B115, sacrificing the cutting stones in a flexible manner.

The steady graph, with oscillations of at most 2-3 points, confirms Miyamoto's assessment of a "masterpiece".

InvincibleTheGamesOfShusaku/Game 36 analyzed with KataGo last edited by on December 6, 2023 - 08:18
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