BillSpightsElfPositionalJudgmentExercises/Game 14 ELf's Solution

White is ahead.  

Elf's recommended continuation for

Elf's mainline for  

Black plays the jump attachment on the third line and then intrudes into the top left corner. White prefers to let Black in instead of letting Black make a territorial moyo on the top side.

Elf's mainline for , continued  

Next, White expands his territory on the right side into the bottom right, preventing Black's kikashi against the White group.

Both of these variations have been lurking for some time.

Earlier in the game.

Sanrensei, slight error  

Elf's winrate estimate for is 7½% less than that for a, making a likely minor error.

Takemiya kosumi, minor errors  

In 1976 I played the kosumi response in a 5 stone game vs. a pro in Kyoto. I don't know when Takemiya had the idea. In any event, Elf thinks that loses 8% to par, and loses 9½%. It believes that each should approach the top left corner. encloses the corner. I don't usually report minor errors, but I thought that these were of some interest. By Elf reckons that Takemiya has lost a net 20% to par.

Black tenuki, significant error  

I was never confident of handling the cut at a, and so avoided the kosumi or blocked at 14. Elf thinks that loses 16½% to the solid connection at a. Considering Black's low winrate estimate after of 33%, we might consider to be a blunder.

Elf's mainline variation for  

After White lives in the corner with the hane-and-connect. OC, the cut at a is smaller than the cut at 19. The territorial footsweep, , is interesting. It does not seem to be in line with the general aim of the sanrensei. After extends, not really making a base because of , and attack the bottom side White group.

Game continuation.

a blunder?  

Elf thinks that , a standard reducing play, loses 16% to par. We should probably consider it a blunder, because White now has a winrate estimate of 95½%.

Elf's mainline variation for  

Black plays kikashi against the White group on the right side, then makes a territorial moyo on the bottom. and intrude into the bottom right. Note that Black's kikashi means that the stone has some aji there.

Elf's mainline variation for , continued  

Next, Black develops the top side, staring with the third line attachment, .

I could have stopped here. However, I do not like to end on a play that Elf considers a mistake, because it typically has very few playouts, and its winrate may not be very reliable. In addition, a series of errors follows, which may be of some interest. :)

Dueling blunders  

looks funny, and indeed, Elf thinks that it loses 16½% to par. It is not unusual to see players trading mistakes of approximately the same size (from Elf's perspective). Perhaps from a mutual blindspot, from shared assumptions or evauations, or from mutual unfamiliarity with such a position. Although in this case Takemiya should be on more familiar territory.

Elf's mainline variation for  

As we have seen before, White expands his territory on the right side. Then plays the jump attachment on the third line against White's enclosure. In this position pulls back to secure territory on the top side and then secures the corner.

Dueling blunders, continued  

looks funny, or impressive, depending on your viewpoint. Elf is not impressed. It thinks that loses 15% to par.

Elf's mainline variation for  

Black takes his kikashi against the right side group and then takes aim at the top left corner, in sequences we have seen before.

Elf's mainline variation for , continued  

In this position does not connect, but approaches the bottom left corner from the bottom side.

Back to the game

Not so bad  

is not so bad, losing only 9½% to par, according to Elf.

Elf's mainline variation for  

By now this sequence is no surprise. :)

Elf's mainline variation for , continued  

In this position Black prefers to approach the bottom left corner from the left side.

One more time.

Black returns the favor, once more  

returns the favor, losing 10½% to par, according to Elf. Then is only a minor mistake. I guess these mistakes are caused by a shared evaluation of this and other areas of the board.

Elf's mainline variation for  

Familiar territory.

Elf's mainline variation for , continued  

By this time, other pros had learned how to play against Cosmic Go. Well, sort of. They still made a lot of mistakes. BTW, Takemiya won by 3½ pts. ;)