Sorry to come late to the party! It's many years since I first read through Invincible. I knew that I'd barely scratched the surface and would need to work through it again one day. Looks like it's time :-)

Back when computers first infiltrated chess analysis, someone coined the term "annotation by result". Pre-computer commentaries (at least for chess) would tend to praise all of the winner's moves, and criticise many of the loser's moves, creating a narrative where the eventual winner of the game was leading all the way. The computers laid bare many reversals of fortunes, and showed that a lot of "easy wins" were not as one-sided as they'd been painted.

Of course temperament is one of the things separating great players from the merely good. The players don't know the computer evaluations during the game. The greats have a deeper well of self-belief which helps them keep looking for resources in a difficult position, complicate things at the right time, snatch victory from the jaws of defeat (as opposed to my own talent for the opposite), ... The computer evaluations don't tell the full story, but I still think it's more interesting if we glance at the decimals enough to notice some of the twists and turns.

"Nightmare" is a strong statement! I just spent a couple of hours going through it. Not simple, but surely not that frightening?

For me on a slightly old setup (KataGo v1.12.4 with network KataGo1.12.4-b18-uec.gz), there's quite a lot of moves where Lizzie "changes its mind" in terms of which move is "blue" -- but the overall evaluation (e.g. black 6.2 points ahead or 89% winrate or whatever) is still pretty stable. This suggests to me that there are many opportunities for trades: "if I play on the right side now, then you'll take profit at the top later; if I play at the top, you'll get the right side"...both options are so finely balanced, as KataGo explores the search tree it will prefer now one, now the other, but the margin will never be large either way.

A good example is after move 13, KataGo doesn't like white's cap in response, but can suggest quite a few viable alternatives. I've previously noted the Lizzie comes out in a rash phenomenon: where the algorithm can't find a clear-cut best move, it will widen the search tree a lot.

Similarly at move 30, I was surprised when white tenukied here. KataGo isn't so sure: it doesn't like the game move, but thinks a local response to B29 and a move at the top are about equally good, and keeps flipping between four alternatives.

There's a long stretch from move 33 to 102 where the top centre is unresolved and both players are ignoring it, so you see the score graph bouncing up and down. This sort of thing makes it a harder to interpret the evaluations. (It happens a lot in my own games, both of us overlooking a vital point, and the computer won't give much feedback on the moves actually played, it just keeps reminding me: hey, you really need to sort out that other situation!) Mostly Shusaku had the initiative and Showa never really had the chance to play at the top, but if Shusaku had played K16 earlier, he could have wrapped up the game with less risk (and the computer evaluations would have looked tidier!)

KataGo found what looks like a clear mistake with the lower left reduction: on move 84, it looks like Showa missed an opportunity to make the game close (and the commentary in Invincible doesn't mention this). Also, black 65 seems to be a missed opportunity.

White's move 110 is fascinating if you look carefully at both the score and the winrate, and compare the alternatives. KataGo seems to be making some interesting risk assessments here. It's late at night in Australia right now, so I'll just drop that hint and come back to it another day if anyone is interested...

I just don't like the game, with all those tenukis and diagonals. Hard to analyze, hard to enjoy.



I got another experience: KG kept suggesting Black drawing out his top stone, out of the entanglement. Not only does that look ugly, KG didn't suggest White to forestall it. When the opponent's good point is not your good point, or even the area, I tend to get nervous.



Yeah, that's about the only logical explanation for the abovementioned asymmetry.



Indeed, interestingly White's improvement chooses thickness above territory. That was a rare enjoyable moment in the analysis



I don't recall anything that late into the game, or is it about that unanswered small knight's jump in the endgame? Will check later. Please do come back!

Click Here To Show Diagram Code

[go]$$Wc19 Castle game 8, position after black 109, white to play
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . b . X O . . . . . . . |
$$ | . . . X c . . . . O X O . . O O X . . |
$$ | . . X d . X X X . X O . . O X . X . . |
$$ | . . O O . . O X . X O . . . X . X X . |
$$ | . . . . O . O . O . O . X . . O X O . |
$$ | . . X . . X O . O . . . . . O . O . . |
$$ | . . . O O . . X . . . . . X . . . . . |
$$ | . . X . . . X . X . . . . . . . O . . |
$$ | . . X O . O . X . a X . . . X . . . . |
$$ | . . . X . X X . . O . . O . . X . O . |
$$ | . . X . . . . . . . . O X X . . O . . |
$$ | . . . . . . . . . O . O X . . . . . . |
$$ | . O O . O . X . X O O X . . O . . . . |
$$ | O . O X X X . . . O X X . . . O . . . |
$$ | . O X O O . X . O . O X . X . . O . . |
$$ | . X X . . O X . X . O . . . X . . . . |
$$ | . . O . O . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ +---------------------------------------+[/go]

No komi; black is a fair bit ahead. Which move would you choose for white?

I completed my own review of the 8th castle game and with some extra effort it was already more enjoyable too

https://senseis.xmp.net/?InvincibleTheG ... WithKataGo

Also, Fujisawa Shuko's analysis is more cautious when he seems to be uncertain and spot on on other occasions.

I'll pause these efforts now.

The theme in this series is thickness, thickness, thickness. On the other hand, there's clearly also psychological warfare going on. Shusaku by no means keeps things simple. In this game he seems to invite Showa into a big brawl. Showa resists and takes territory when he feels the pressure mounting. That allows Shusaku to regain his infamous thickness and use it to take victory home in the endgame.