Reviewing Shuko's book with bots

Uberdude · Post by **Uberdude** » Tue Dec 10, 2019 3:56 am

There's been quite a lot of activity recently on the thread Reviewing SL using LZ and criticism. I am making this thread as both an interesting study of Go positions, but also highlights that applying the standard of "approved by LZ" is actually an incredibly high standard of quality that much of Go literature fails to meet, whether random Western amateur's scribblings on SL or the thoughts of the great honorary Kisei Fujisawa Shuko 9p, widely admired for his skill in the opening and early middlegame, in a published book. (This is not to say I don't think we should strive to improve them with the tools we now have).

The problem(s) I will study come from the book "Shuko: the only move, volume 2, fighting middlegame collection". These come from his comments on study session games of 'young' players so I believe do really reflect his thoughts (via translation) rather than those of a ghost writer, as can happen with other books with a pro's name on the cover. I did some similar anaylses a while back on a thread in the computer go subforum.

For the first analysis, I used Ah Q Go running a 15-block LZ on my mobile phone with a few hundred to few thousand playouts so that we can see how strong a phone is (does it have a better intuition than Shuko but make reading mistakes?), and then I will do a second-pass using many playouts of LZ/Elf/KataGo on my GPU.

The extension of starts an intense skirmish. Is it possible to kill two birds with one stone by pressing White closely, while reinforcing Black's own position? It must be a flexible move, that is a hint.

Click Here To Show Diagram Code: [go]$$Bc Problem 11, Black to play $$ +---------------------------------------+ $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O X X X . . Q . . O . X . . . . . | $$ | . O . O . . O . . , . . . . . , X . . | $$ | . . . O X X . . . . . . . . . . . . . | $$ | . . . . O . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . X . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O O . . . . . . . . . . . . . . . | $$ | . . X . . . . . . . . . . . . . . . . | $$ | . . . . O . . . . . . . . . . . . . . | $$ | . . . O . . . . . , . . . . . O . . . | $$ | . . X X . X . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ +---------------------------------------+[/go]

Before giving his answer, Shuko gives a brief review of any major mistakes he sees so far. How well will this agree with LZ? Without even checking order of play I can predict that it won't like:
- white's kosumi at lower left, that's a slack shape, should attach
- lower right hasn't been 3-3ed or approached, that will have been preferred as a bigger and more urgent move over other moves already played
- top left looks like that table shape joseki, but white didn't push through like AG taught us (but the pincer is looser than normal, will that change things?)
- black one point jump on left side is rather vague and not doing much efficiently
- white hanging connection top left should probably have been descend.

Here is the course of play, white was Yokota Shigeaki 9p, black Kenmochi Jo 7p. Shuko doesn't criticise anything here just saying how black would have made the mini-Chnese if 5 responded at 9 and "When white starts operations in the upper left with 6 and 8 black first fixes the shape in the lower left with 9 through 13, and then responds with 15, setting a rapid pace."

Click Here To Show Diagram Code: [go]$$Bc $$ +---------------------------------------+ $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . 3 . . . . . . . . . . . . . . . | $$ | . . . , . . 8 . . , . . . . . , 1 . . | $$ | . . . 6 . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . 7 . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . 5 . . . . . . . . . . . . . . . . | $$ | . . . . 0 . . . . . . . . . . . . . . | $$ | . . . 2 . . . . . , . . . . . 4 . . . | $$ | . . . . . 9 . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ +---------------------------------------+[/go]

Phone LZ likes 6 (or other approaches) over back off at 9 (-2%, as this is weaker LZ than recent 40-blocks the %s are smaller), which is unsurprising given The opening gospel according to LZ. 7 is of course bad (-3%), being an even looser pincer than the ones humans commonly play which bots still don't like, attach under at c15, or shimari top left or approaching/invade 4-4s are better moves, as the gospel tells. (NB I think that amateur dan players like myself and maybe even kyus can play a better first 20 moves of the game than these pros simply by following that gospel). 8 is also bad, should attach c17 (corners are king) or approach top left. 9 is ok, but would prefer to c15 attach first to take corner points and eyes in sente. 10 kosumi is bad (-5%, worse move of game so far) as predicted.

No comments from Shuko on this

Click Here To Show Diagram Code: [go]$$Bcm11 $$ +---------------------------------------+ $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . 0 X . 9 . . . . . . . . . . . . . | $$ | . . . 8 . . O . . , . . . . . , X . . | $$ | . . . O 5 7 . . . . . . . . . . . . . | $$ | . . . . 6 . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . 4 2 . . . . . . . . . . . . . . . | $$ | . . X . . . . . . . . . . . . . . . . | $$ | . . . . O . . . . . . . . . . . . . . | $$ | . . . O . . . . . , . . . . . O . . . | $$ | . . 1 3 . X . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ +---------------------------------------+[/go]

Finally with 11 we get a #1 LZ move, 12 again off-topic (c17 or top right), 13 is correct, these pros can at least answer sente moves correctly. For 14 LZ wants to play an interesting move that was unexpected to me at d9: this prepares to block at c4 to develop the left side and puts some pressure on the pincer, c7 is -7% as (my interpretation) when black plays c5 you got no territory, no eyes, have a cut at e7 and aren't attacking d9, you just made a heavy little wall. Attaching at 15 to cut big knight is a move AG didn't like either, LZ recommends f14 3% better. Instead of 19 table shape wants e17 extend (1k playouts) but when played actually prefers table a bit, and then doesn't want to push through but hane in corner like the pro.

Shuko no comments til 24, see later

Click Here To Show Diagram Code: [go]$$Bcm21 $$ +---------------------------------------+ $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O X 1 X . . 6 . . 4 . 5 . . . . . | $$ | . 2 . O . . O . . , . . . . . , X . . | $$ | . . . O X X . . . . . . . . . . . . . | $$ | . . . . O . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . 3 . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O O . . . . . . . . . . . . . . . | $$ | . . X . . . . . . . . . . . . . . . . | $$ | . . . . O . . . . . . . . . . . . . . | $$ | . . . O . . . . . , . . . . . O . . . | $$ | . . X X . X . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ +---------------------------------------+[/go]

LZ says c18 descent considerably (6%) better as I predicted, I suppose the pro didn't like that black could then cut at d14 whereas hanging connect allow that to be captured with d13, but cut is a bad move and w simply ataris from under and pushes and then takes sente happy with a large corner and still cutting stone aji. In fact after c18 best move for black is not cut but c13 peep. The weird 23 is only -3%. So LZ, and also me following the gospel, see numerous mistakes so far which Shuko didn't see as major enough to comment on, how will they compare in size to 24 which he does criticise?

He says

I suppose that the result through black 23 is reasonable, but what about white 24 here? I guess that white thinks if the group on the upper side is settled then the black group in the upper left can be attacked. Instead, one wants to attack the white corner with [below]. Should black defend with 2 through 6 the extension of 7 works effectively for white.

In regards to using to make a pincer on the upper side,,, well, black is weak in the upper left but there is no pincer that fits the bill precisely.

I suppose that for a is also possible. If white can slowly get into the centre, black will become weak on the left and upper sides.

Click Here To Show Diagram Code: [go]$$Wc $$ +---------------------------------------+ $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O X X X . . 7 . . . . 3 2 4 . . . | $$ | . O . O . . O . . , . . 5 . 1 , X . . | $$ | . . . O X X . . . . . . . . . . . . . | $$ | . . . . O . . . . . . . . . . . 6 . . | $$ | . . . . . . a . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . X . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O O . . . . . . . . . . . . . . . | $$ | . . X . . . . . . . . . . . . . . . . | $$ | . . . . O . . . . . . . . . . . . . . | $$ | . . . O . . . . . , . . . . . O . . . | $$ | . . X X . X . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ +---------------------------------------+[/go]

LZ agrees that high approach is better than the wedge, no surprise there, corners before sides as the proverb and gospel tell us. But it's not by much, following wedge it agrees with 25 and 26 and white is at 52%, but after high approach it's only 54%, ie this mistake is several times smaller than other mistakes so far which went unremarked. Interestingly LZ thinks the best response to high approach is the unusual 2-space low pincer than AG also recommended in teaching tool. And it thinks low approach was 1.5% better than high, so Shuko's suggested move is almost as much a mistake from the best move as the real game's move was from Shuko's suggestion. What of Shuko's judgement that if black follows the standard joseki white 7 is good? LZ strongly agrees, white is up to 62% now, but that's because black played bad moves to make Shuko's move look better than it deserved (a common trait I've noted in his sequences). 2 was a little bad (and Shuko did at least consider a pincer but say nothing looks satisfactory, which seems fair enough if the best move is the wacky pincer), but the chief fault lies with the cooperative black 6. As bots have taught us the hanging connection of 5 is not sente so black should have taken the key point of mutual extension and eyespace point of j17 for himself for 51%, instead of losing 13% at r14. So Shuko's illustrative sequence contains a mistake from the opponent far larger than any in the game so far and the initial mistake he was correcting. It was at least given as a conditional "Should black play 2 etc..." and he did consider pincer instead of 2, but he didn't, or at least not recorded in the book, consider a stronger resistance for black further down his sequence. I could well imagine if black did play such an extension he would not be too peturbed and press the corner as those 2 areas are generally consider miai in the joseki, but LZ is saying that relying on this joseki judgement that they are miai is wrong here because the top side is more valuable due to black's weak group there. What white should have done is either solid connect because that is more sente than hanging, but even so black should STILL tenuki to j17 and allow white q14 or r15, or just directly take the vital point at j17 and allow black to cut, or if black defends at f14 then white can o16 connect.

I wouldn't claim that Shuko should have highlighted the move with the absolute biggest win% drop in the game so far as the one for criticism, as the move with the most valuable teaching lesson that can be well extracted into explainable ideas and re-applicable valuable principles might not be the same, but to highlight a 2% mistake (vs his suggestion) and then make a 13% mistake in his sequence to justify why his move is better, whilst ignoring several >5% mistakes in the game means I give a pretty poor "LZ approved" score so far.

Uberdude · Post by **Uberdude** » Tue Dec 10, 2019 4:53 am

Now, what for the problem itself? My instinct was to make the thick turn at f14 and Shuko was well known for liking thick turns, but it didn't really seem to fit with the hint of "a flexible move". And it wasn't Shuko's answer, but it was (phone) LZ's! So is my instinct and phone stronger than Shuko in this instance? That'll have to wait until I check with my GPU which I'm sure is stronger than Shuko so can be trusted. But what was the game move and is Shuko's at least better than that?

Kenmochi played this odd L15 move which wasn't even on LZ's or my radar, white jumped and then black turned. Did he see this as inducing the turn?

Click Here To Show Diagram Code: [go]$$Bcm27 Game continuation, 37... at a-d $$ +---------------------------------------+ $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O X X X . . O 0 . O . X . . . . . | $$ | . O . O . . O . . 9 . . . . . , X . . | $$ | . . . O X X . . 2 . 1 . . . . . . . . | $$ | . . . . O 3 . . . . . . . . . . . . . | $$ | . . . . 4 5 . . . . . . . . . . . . . | $$ | . . . . 8 6 7 . . . . . . . . . . . . | $$ | . . . X b X a . . . . . . . . . . . . | $$ | . . . d c . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O O . . . . . . . . . . . . . . . | $$ | . . X . . . . . . . . . . . . . . . . | $$ | . . . . O . . . . . . . . . . . . . . | $$ | . . . O . . . . . , . . . . . O . . . | $$ | . . X X . X . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ +---------------------------------------+[/go]

Shuko says:

This attacks white on the upper side, but when white jumps at 28 black's group in the upper left comes under attack.
Black fixed the shape on the left side with 29 and the following moves, but unless a severe attack can be mounted against white on the upper side black's thickness in the centre will not work effectively.
Defending against 35 at 36 makes it easy for white's group to survive.
It is unreasonable for black to use 37 to connect at 38 as white can cut at 37.

Before we get into what LZ and Shuko think was better, does LZ at least agree with his judgement of the problems of the game line? Phone LZ indeed says 27 is pretty bad at -9%, 28 (which Shuko presumably thought was fine) is almost as bad at -7% (should be e12 peep an fun fight). 29 and 30 are good, 31 is bad (-5%) because the wedge of 32 is powerful so black should have dodged to h14. 35 was off-topic, white's best answer was tenuki to e11 push, 2nd best was j16 connect and 3rd best the game k17 connect Shuko approved of. And then 37 which he said was unreasonable to e11 is only move and game outside connection lost 7%. But white does at least end this sequence at 55%, which is a little better than the 51% he started at before black played the L15 Shuko picked out to criticise (but less than the ups-and-downs in the sequence).

Shuko said it was unreasonable for black to connect at e11, LZ says its the best move, let's see how it handles the fight he was scared of. Note that by making the 35-36 exchange the e11 connect is now even better for black than before in LZ's eyes because of the j16 weakness created.

Click Here To Show Diagram Code: [go]$$Bcm37 LZ handles the fight Shuko said was unreasonable $$ +---------------------------------------+ $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O X X X . . O O . O . X . . . . . | $$ | . O . O . . O . . X . . . . . , X . . | $$ | . 0 . O X X . . O . X . . . . . . . . | $$ | . 9 . 4 O X . . . . . . . . . . . . . | $$ | . . 3 . O X . 5 . . . . . . . . . . . | $$ | . . . . O O X . . . . . . . . . . . . | $$ | . . . X 1 X 2 b . . . . . . . . . . . | $$ | . . . . . . 6 . . , . . . . . , . . . | $$ | . . 7 a 8 . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O O . . . . . . . . . . . . . . . | $$ | . . X . . . . . . . . . . . . . . . . | $$ | . . . . O . . . . . . . . . . . . . . | $$ | . . . O . . . . . , . . . . . O . . . | $$ | . . X X . X . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ +---------------------------------------+[/go]

If white cuts for 38, black gets the juicy peep of 39 (in fact LZ thinks white shouldn't even cut but defend at 39 and let black defend the cut!) and black is at 50%. Black defends the cut in the centre with hanging connect (this and h12 extend close candidates), white extends the cutting stone, black makes some eyespace on the side (rather than running out) and white seals in. Note here what a difference it would have made if white had played the d9 instead of c7 block earlier, black's group would not have so much room and this fight would indeed have been harder for black. For 47 LZ thinks about spending a move to safely live at a or play a move in centre fight at b at which point white starts doing mean things to the left. With just a few hundred playouts on my phone I think LZ might misjudge the life and death status here, something to check later. Indeed as I give it more playouts it flits back to spending a move on the left because it sees a variation of it dying with a 4 stone nakade if tenuki.

Shuko gives black playing at white 28 as the answer:

Black 1 is the only move to play next. By attacking white on the upper side black takes hold of the initiative in the fighting.
Jumping with white 2 would be standard. Then by keeping on the pressure with 3 black solidifes the corner. In addition, if white plays 4 black replies with 5. This links the positions on the upper and left sides, while at the same time causing white's group in the lower left to become a target. White cannot fight strongly.

Click Here To Show Diagram Code: [go]$$Bc Shuko's answer $$ +---------------------------------------+ $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O X X X . . O . . O . X . . . . . | $$ | . O . O . . O . . , . . . . . , X . . | $$ | . . . O X X . . 1 . . 2 . 3 . . . . . | $$ | . . . . O . . . . . . . . . . . . . . | $$ | . . . . . . . . 5 . . 4 . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . X . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O O . . . . . . . . . . . . . . . | $$ | . . X . . . . . . . . . . . . . . . . | $$ | . . . . O . . . . . . . . . . . . . . | $$ | . . . O . . . . . , . . . . . O . . . | $$ | . . X X . X . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ +---------------------------------------+[/go]

Before

LZ gave black 50% (and after f14 turn too as best move). The real game L15 took that down to 41%. After Shuko's j15 LZ gives black 46% on low playouts when it has white answering at c4, but this drops down to 43% as it finds an exquisite riposte with a few hundred playouts. First what of Shuko's sequence, as before it is given with some conditionallity on white's replies "would be standard", "if white plays 4". Well, having an idea of what to do if standard is all well and good as a starting point for playing at a high level, but really you should be prepared for your opponent to resist your plans and try to find an even better move. Phone LZ does consider m15 jump and gives black 47%, but other moves it likes more (but less than the amazing #1 for later) are p17, q17 and q16 operations against top right shimari, l15 different jump, e12 peep, c4 block, h14 or g13 cut. All these moves make sense to me as candidate moves a strong player could consider. If white indulges Shuko with m15, then LZ thinks 3 is also soft, it prefers to peep at L16, white connects and then k18, avoiding this peep is probably why it had a slight preference for l15 jump instead. It also likes tenuki to b5, which makes sense as white c4 was a good move before so it's big to connect up there. If m15 was soft before (-5%) then m13 jump is even softer (-6%). White should instead begin operations to cut j15 with e15, h14 or other moves in that area. LZ is not a fan of 5 either (-6%), preferring the thick f14 turn (with maybe l16 peep first), which does seem much more Shuko thick style to me.

How does LZ refute Shuko's answer? His justification of 5 as linking up black's position gives a big clue, as does that LZ wanted to play the thick f14 turn instead. White would like to cut off j15 at h14, but is too thin on the left at the moment. So LZ suggests the bold leaning attachment at f12. That this move exists further vindicates my feeling that the f11 jump was poor.

Click Here To Show Diagram Code: [go]$$Bc LZ refutes Shuko's answer $$ +---------------------------------------+ $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O X X X . . O . . O . X . . . . . | $$ | . O . O . . O . . , . . . . . , X . . | $$ | . . . O X X . . 1 . . . . . . . . . . | $$ | . . . . O . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . 2 . . . . . . . . . . . . . | $$ | . . . X . X . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O O . . . . . . . . . . . . . . . | $$ | . . X . . . . . . . . . . . . . . . . | $$ | . . . . O . . . . . . . . . . . . . . | $$ | . . . O . . . . . , . . . . . O . . . | $$ | . . X X . X . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ +---------------------------------------+[/go]

Black has several ways to reply, first what if just nobi into the centre? This clarifies the purpose of white's attachment as building some strength in sente to allow the h14 cut, now if black pushes and cuts with a-c it's a disaster and black is dying inside. So black wouldn't play a but turn at f14 and those 2 forcing exchanges show their value in blocking black's exit: there's some fighting but the general story is black will have to live at h18 so white gets out into the centre and j15 is disconnected. Maybe a human wouldn't like the "inside for outside" exchanges with black getting a big stick on row 11 but LZ sees this as acceptable to make black live miserably on the top and cut j15. Plus it's just an eyeless wall, right?

Click Here To Show Diagram Code: [go]$$Bcm3 LZ refutes Shuko's answer, variation 1 $$ +---------------------------------------+ $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O X X X f . O . . O . X . . . . . | $$ | . O . O . . O . . , . . . . . , X . . | $$ | . . . O X X b a X . . . . . . . . . . | $$ | . . . . O d c 4 . . . . . . . . . . . | $$ | . . . . . . e . . . . . . . . . . . . | $$ | . . . . 2 O . . . . . . . . . . . . . | $$ | . . . X 3 X 1 . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O O . . . . . . . . . . . . . . . | $$ | . . X . . . . . . . . . . . . . . . . | $$ | . . . . O . . . . . . . . . . . . . . | $$ | . . . O . . . . . , . . . . . O . . . | $$ | . . X X . X . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ +---------------------------------------+[/go]

After 1k playouts LZ decides that black was being too obedient above, and he should turn in the centre for 5: the connectivity here is more valuable than the e11 hole. LZ white then bamboos in sente for shape (now that black spent a move 5 letting him connect to j15 is ok) and then pushes and cut for left side profit at 60%. It did also consider q17 invasion. LZ thinks allowing black to attack the top side is fine, white was too cautious when jumping at m15.

Click Here To Show Diagram Code: [go]$$Bcm3 LZ refutes Shuko's answer, variation 1a $$ +---------------------------------------+ $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O X X X . . O . . O . X . . . . . | $$ | . O . O . . O . . , . . . . . , X . . | $$ | . . . O X X 5 . X . . . . . . . . . . | $$ | . . . . O 4 . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . 2 O 3 . . . . . . . . . . . . | $$ | . . . X 6 X 1 . . . . . . . . . . . . | $$ | . . . 8 7 . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O O . . . . . . . . . . . . . . . | $$ | . . X . . . . . . . . . . . . . . . . | $$ | . . . . O . . . . . . . . . . . . . . | $$ | . . . O . . . . . , . . . . . O . . . | $$ | . . X X . X . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ +---------------------------------------+[/go]

The other major choice to respond to the f12 attachment is tenuki to take the mutual base point at h18, and after more playouts this is #1 choice. White blocks on top inviting black to save the stone in gote, he declines and connects f15 so white gets to follow-up the ignored attachment and then comes back to live on top at 58%.

Click Here To Show Diagram Code: [go]$$Bcm3 LZ refutes Shuko's answer, variation 2 $$ +---------------------------------------+ $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . 8 1 . . . . . . . . . . . | $$ | . . O X X X . 2 O . . O . X . . . . . | $$ | . O . O . . O . . , . . . . . , X . . | $$ | . . . O X X 3 . X . . . . . . . . . . | $$ | . . . . O . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . 6 O . . . . . . . . . . . . . | $$ | . . . X . X 4 . . . . . . . . . . . . | $$ | . . . . . 5 . . . , . . . . . , . . . | $$ | . . 7 . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O O . . . . . . . . . . . . . . . | $$ | . . X . . . . . . . . . . . . . . . . | $$ | . . . . O . . . . . . . . . . . . . . | $$ | . . . O . . . . . , . . . . . O . . . | $$ | . . X X . X . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ +---------------------------------------+[/go]

So if white resists Shuko's j15 black only ends with 40-42%. Finding f12 and correctly evaluating is hard, but I expect some top pros could do it, so I'd call it hard but doable to refute Shuko's answer.

LZ's answer to the problem though, f14 thick turn, was easy for me to find and gives black 50%. Expected continuations are either for white to naturally extend at e14, or c4 block to settle that group. If the former black takes the c13 peep (aka profit in sente causing inefficiency), white slips in the cut before connecting, black hanging connects at the top and then settles on the left similar to the previous variation of LZ showing Shuko shouldn't be scared of the cut in actual game.

Click Here To Show Diagram Code: [go]$$Bc LZ's answer, variation 1, 11-13 a-c $$ +---------------------------------------+ $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O X X X . . O . . O . X . . . . . | $$ | . O . O . . O . . , . . . . . , X . . | $$ | . . . O X X . . . . . . . . . . . . . | $$ | . . 8 . O 1 . 9 . a . . . . . . . . . | $$ | . . 3 . 2 6 7 . . . . . . . . . . . . | $$ | . . . . . 5 4 0 . . . . . . . . . . . | $$ | . . . X . X . . . . . . . . . . . . . | $$ | . . . , . . . b . , . . . . . , . . . | $$ | . . c . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O O . . . . . . . . . . . . . . . | $$ | . . X . . . . . . . . . . . . . . . . | $$ | . . . . O . . . . . . . . . . . . . . | $$ | . . . O . . . . . , . . . . . O . . . | $$ | . . X X . X . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ +---------------------------------------+[/go]

LZ sees white c4 as very valuable and it rises to top choice, here's a continuation. Black presses to blockade the top, white 6 is a move we normally are told is bad but white lives on top allowing black influence, but in living in the k15 area white makes e13 become sente on the f17 group.

Click Here To Show Diagram Code: [go]$$Bc LZ's answer, variation 2 $$ +---------------------------------------+ $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . b . . . . . . . | $$ | . . O X X X . . O 4 . O 7 X . . . . . | $$ | . O . O . . O . . 3 8 5 6 . . , X . . | $$ | . . . O X X . . , d 0 9 . . . . . . . | $$ | . . . . O 1 . . . g c a . . . . . . . | $$ | . . . . f . . . . . . . . . . . . . . | $$ | . . . . . h . . . . . . . . . . . . . | $$ | . . . X . X . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , e . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O O . . . . . . . . . . . . . . . | $$ | . . X . . . . . . . . . . . . . . . . | $$ | . . . . O . . . . . . . . . . . . . . | $$ | . . 2 O . . . . . , . . . . . O . . . | $$ | . . X X . X . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ +---------------------------------------+[/go]

Click Here To Show Diagram Code: [go]$$Bcm11 LZ's answer, variation 2 contd. $$ +---------------------------------------+ $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . 2 . . . . . . . | $$ | . . O X X X . . O O . O X X . . . . . | $$ | . O . O . . O . . X O X O . . , X . . | $$ | . . . O X X . . , 4 O X . . . . . . . | $$ | . . . . O 1 . . . 7 3 1 . . . . . . . | $$ | . . . . 6 . . . . . . . . . . . . . . | $$ | . . . . . 8 . . . . . . . . . . . . . | $$ | . . . X . X . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , 5 . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O O . . . . . . . . . . . . . . . | $$ | . . X . . . . . . . . . . . . . . . . | $$ | . . . . O . . . . . . . . . . . . . . | $$ | . . O O . . . . . , . . . . . O . . . | $$ | . . X X . X . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ +---------------------------------------+[/go]

Bill Spight · Post by **Bill Spight** » Tue Dec 10, 2019 6:36 am

Uberdude wrote:As bots have taught us the hanging connection of 5 is not sente so black should have taken the key point of mutual extension and eyespace point of j17 for himself for 51%, instead of losing 13% at r14. So Shuko's illustrative sequence contains a mistake from the opponent far larger than any in the game so far and the initial mistake he was correcting.

This is a pitfall that I have noticed when composing problems. When you have a point to make you tend to forget everything else.

It's not like humans did not know that the hanging connection is not sente. IIRC, Fujisawa himself, in a game against Sakata, did not treat the hanging connection as sente but played the equivalent of K-16 in this orientation. (OC, the rest of the board was completely different.) Everybody needs a good editor.

Bill Spight · Post by **Bill Spight** » Tue Dec 10, 2019 6:55 am

Many thanks, Uberdude, for this thread. Not only do we get Fujisawa's thoughts and LZ's plays, but your critiques and explanations. A threefer!

Uberdude · Post by **Uberdude** » Wed Dec 11, 2019 3:23 am

I did a brief check on what LZ 254 at min 10k playouts thought of phone LZ's opinions. It always agreed with phone LZ's moves being better than Shuko's (and agreed thick f14 turn was strongly the only move in answer to the problem, though at 54% after 350k playouts) but sometimes saw even better ones or saw slight improvements. For example it DID want to push through the table shape, and also saw some finesse to move orders, for example if you recall phone LZ after the f12 attachment (which LZ 254 agrees with and finds event faster than phone) wanted to extend at 4 below, initially expecting black to connect at 8 and then was going to cut at h14, but then found that black did better to not connect but turn in the centre at 5.

Click Here To Show Diagram Code: [go]$$Bcm3 Phone LZ refutes Shuko's answer, variation 1a $$ +---------------------------------------+ $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O X X X . . O . . O . X . . . . . | $$ | . O . O . . O . . , . . . . . , X . . | $$ | . . . O X X 5 . X . . . . . . . . . . | $$ | . . . . O 4 . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . 2 O 3 . . . . . . . . . . . . | $$ | . . . X 6 X 1 . . . . . . . . . . . . | $$ | . . . 8 7 . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O O . . . . . . . . . . . . . . . | $$ | . . X . . . . . . . . . . . . . . . . | $$ | . . . . O . . . . . . . . . . . . . . | $$ | . . . O . . . . . , . . . . . O . . . | $$ | . . X X . X . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ +---------------------------------------+[/go]

On my PC LZ 254 sees this and thus realises white should DIRECTLY cut at h14 because e12 is not sente enough. A finessed move order that's less than 0.1% better but seems entirely logical when you are shown it. It results in this trade as best for both. Note that the purpose of white d12 is to make black f13 gote so black shouldn't connect at d10 or else white cuts at g13 now that f13 can be answered at h15 and black is worse.

Click Here To Show Diagram Code: [go]$$Bcm3 LZ 254 refutes Shuko's answer, variation 1a improved more order for slightly better result $$ +---------------------------------------+ $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O X X X . . O . . O . X . . . . . | $$ | . O . O . . O . . , . . . . . , X . . | $$ | . . . O X X . 9 X . . . . . . . . . . | $$ | . . . . O 3 . 2 . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . 8 4 O 5 . . . . . . . . . . . . | $$ | . . . X 6 X 1 . . . . . . . . . . . . | $$ | . . . 0 7 . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O O . . . . . . . . . . . . . . . | $$ | . . X . . . . . . . . . . . . . . . . | $$ | . . . . O . . . . . . . . . . . . . . | $$ | . . . O . . . . . , . . . . . O . . . | $$ | . . X X . X . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ +---------------------------------------+[/go]

xela · Post by **xela** » Sat Dec 14, 2019 11:58 pm

Uberdude wrote: ...Phone LZ does consider m15 jump and gives black 47%, but other moves it likes more (but less than the amazing #1 for later) are p17, q17 and q16 operations against top right shimari, l15 different jump, e12 peep, c4 block, h14 or g13 cut. All these moves make sense to me as candidate moves a strong player could consider.

It's interesting to look at LZ's policy values here.

Click Here To Show Diagram Code: [go]$$Bc LZ's high policy moves (network number 242) $$ +---------------------------------------+ $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O X X X . . O . . O . X . f . . . | $$ | . O . O . . O . . , . . . . . j X . . | $$ | . . . O X X . . 1 . e d . . . . . . . | $$ | . . . . O . . c . . . . . . . . . . . | $$ | . . . . . . h . . . . . . . . . . . . | $$ | . . . . b f . . . . . . . . . . . . . | $$ | . . . X . X . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O O . . . . . . . . . . . . . . . | $$ | . . X . . . . . . . . . . . . . . . . | $$ | . . . . O . . . . . . . . . . . . . . | $$ | . . a O . . i . . , . . . . . O . . . | $$ | . . X X . X . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ +---------------------------------------+[/go]

Image behind the cut with the numbers for each marked point:

You can see how LZ was initially pretty keen on the C4 block but went off the idea with some reading, and why it takes so many playouts to find the F12 move.

Life In 19x19

Reviewing Shuko's book with bots

Reviewing Shuko's book with bots

Re: Reviewing Shuko's book with bots

Re: Reviewing Shuko's book with bots

Re: Reviewing Shuko's book with bots

Re: Reviewing Shuko's book with bots

Re: Reviewing Shuko's book with bots