InvincibleTheGamesOfShusaku/Game 35 analyzed with KataGo

Moves 1 to 10  

Obviously the fight stems from a taisha joseki.

Moves 11 to 20  

Sanno says is no longer the standard move but the joseki of the time of commenting is also no longer valid by modern insights. Even the whole taisha has actually disappeared.

Also is "the wrong side of the corner". Sanno recommends 4-4 or 3-3 instead. The reason is that the top is influenced by Black and White should emphasize the corner.

Book proposal for 13  

The bad looking empty triangle makes miai of and .

AI proposal for 13  

The AI proposal is somewhat similar but puts more pressure on the opponent stones.

Book proposal for 20, locally  

Apart from criticizing the particular choice in the upper left, the book says the area is not urgent in the first place and it might be better to continue locally. AI doesn't like this so much, as it allows Black to play in the open corner(s) first.

AI proposal for 20, locally  

AI suggests this . Black needs to prevent an attack so can occupy the empty corner.

Moves 21 to 30  

Sanno critizes for being the wrong direction. KataGo locally prefers the outside attachment and globally continuing in the upper right or taking an open corner, but all of it by a small margin. The main reason why it seems to dislike is because Black can now easily tenuki and White can't take the corner efficiently. From various local suggestions by KataGo it seems to value the top side more than anything. While Sanno thinks Black's influence is to stay away from, KataGo treats it more like a potential target.

Hence it approves of but likes A a little better. KataGo would solve White's issues differently:

Faster  

is using the aji on the right side to move faster into the center.

Moves 31 to 40  

The fight continues. Sanno likes the flow for Black. KataGo dislikes : the focus is on the running fight into the center. A is the vital point. Hence is an overplay according to KataGo.

Moves 41 to 50  

However, Black's bamboo is slow. It allows White to occupy the vital point with . Simply moving out diagonally would have been more efficient.

The book discusses at length the top right life and death. Moves in the vicinity of are sente to that group because a ko can be launched. ix kikashi before living. Sanno calls it exquisite timing. KataGo holds an alternative idea.

Sacrifice - at  

KataGo indicates that capturing the upper right requires a lot of work, since White has a big eye. So it is possible for White to sacrifice the corner, playing the thick escape of , then allow Black to win the ko by taking a big point with . When connects the ko, White has forcing moves at A and B. White could even exploit Black's bad shape with C and D.

This position is a good example of AI's extreme flexibility. It will continue locally as long as the stones can be used efficiently but as soon as the situation reverses, it will play elsewhere and sacrifice.

Moves 51 to 60  

If had an interesting strategic alternative, is plain wrong says KataGo. Black should simply connect with good shape at A. That would of course still leave the aji for the corner to escape but KataGo seems less concerned with that corner and more with the balance of power in the center.

Sanno calls submissive but unavoidable. KG agrees White is falling behind but suggests fighting back at A.

Also KataGo disapproves of Black's tenuki. It's a common feature of strong humans to play away after having forced the opponent and obtain a favorable exchange like -. But KG indicates the whole board fighting is not over yet. Locally, Black can simplify at B, globally keep on the pressure with C or even cut at D. Once more we see how AI is not straightforward in its preference for open corners. As long as the local situation affects the efficiency of the stones involved, it prefers to continue. Black's tenuki at amounts to a 4 point mistake!

shows Yasui Sanchi's fighting spirit but both Sanno and KataGo think it's too much. KataGo prefers C again for White. It seems to be the vital point globally.

Moves 61 to 70  

leads into a classic sacrifice tactic, allowing the extension at . Sanno applauds it, KataGo thinks White gets too easy life at the top. Also, is pushing White over Black's weaker group, while building influence to the less interesting left side. Black's cut at A can now be met with White B, so there's not much of a threat going on there.

is the point of the game where it gets close. This is a pattern in these evaluations of Shusaku's castle games with AI. It seems like Shusaku allows White to slowly get into the no komi game, to then widen the gap again from the late middle game onwards. This might point to Shusaku being relatively stronger in the late middle game but it might also indicate that he was able to build a position in the early stage from where it was easier to manufacture a win.

Interestingly, Sanno thinks the game is over after . Here the professional assessment of Black's overall superiority is not confirmed by KataGo's expected result.

Moves 71 to 80  

Sanno calls a typical solid move when you are comfortably ahead. KataGo is not so sure about that: yes, is lukewarm but no Black is not ahead more than 2 points.

Sanno also criticizes : it should be farther to the left, when playing at the bottom. KataGo thinks it should continue on the right side:

Alternative  

KataGo is more occupied with the relative strength of the groups than with developing the bottom.

Moves 81 to 90  

After both take big points before urgent ones, Black resolves the situation with . KataGo thinks White can fight back at with and should also unleash the aji higher up at A. Even after the sequence here White could do so.

is not enough to win according to Sanno. He thinks White should invade at A, apopular probe.

alternative for  

A standard technique to set up a ko.

Moves 91 to 100  

Sanno thinks the game is hopeless for White by but KataGo thinks it's still close. White could apply leverage on the lower left corner and threaten an attack on Black's top group. at A could be such a starting point.

White chooses a more direct approach with which Sanno assesses as a worthless peep, since can push through. backs off but KG thinks simply blocking was better.

blocking  

If blocks here, Black can indeed take sente but then White can make territory naturally while attacking the center.

Moves 101 to 110  

When turns here, loses tempo and White has to return at , so that Black comes out in sente and can reinforce at .

With that, it's indeed quite impossible for White to get back into the game. KataGo's evaluation at this point is B+5 There is still some aji in that top group but Black can live at A or come out at B, so there's not really a big problem for Black.