Shapes to remember (SDK level)

Knotwilg · **#121**

jlt · **#122**

Hint

Katago's main line

Further comments

If Black cuts first, Katago's main line is the following, and is 3 points worse:

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

Knotwilg's idea is 7 points worse than the main variation.

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

Note that Black finishes in gote.

Knotwilg · **#123**

Your main line has two 6's and 7's.

jlt · **#124**

I corrected the diagram.

jlt · **#125**

Position #68, Black to play. Find the next few moves.

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

lightvector · **#126**

This position feels a bit unusual, because it seems Black may have missed the typical joseki move in the upper right? Unless there is a different sequence that leads to that result.

In the joseki I know that results in a shape like the upper right, normally Black plays a hane at R18 instead of merely extending at Q18. White blocks, Black connects, then White needs to add another move to not die, which is usually at S13.

Click Here To Show Diagram Code: [go]$$Bc $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . X X X . . . . . . . . . . B B W . | $$ | . . O X O X X . . . . . . . . X O . . | $$ | . . . O O O X . . , . . . . . X O . . | $$ | . . . . . . O X . . . . . . X O O . . | $$ | . . O . . . O X . . . . . . . X O . . | $$ | . . . . . . . . . . . . . . . X . W . | $$ | . . . . . . . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . O . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . O O . . | $$ | . . . . . . . . . . . . . . . O X . . | $$ | . . . , . . . . . , . . . . . , X . . | $$ | . . O . . . . . . . . . . X . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Although I guess it's a little uncommon regardless that white still gets to play this clamp much later, as it is common for black to add a defense here to stop the clamp.

Anyways, it may be instructive to compare and contrast how Black should handle White's clamp in the perhaps-more-standard shape, as follows:

Click Here To Show Diagram Code: [go]$$Bc Black to play here, as a contrast/complement to jlt's position $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . X X X . . . . . . . . . . X X O . | $$ | . . O X O X X . . . . . . . . X O . . | $$ | . . . O O O X . . , . . . . . X O . . | $$ | . . . . . . O X . . . . . W X O O . . | $$ | . . O . . . O X . . . . . . . X O . . | $$ | . . . . . . . . . . . . . . . X . O . | $$ | . . . . . . . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . O . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . O O . . | $$ | . . . . . . . . . . . . . . . O X . . | $$ | . . . , . . . . . , . . . . . , X . . | $$ | . . O . . . . . . . . . . X . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

jlt · **#127**

Indeed I (Black) missed the hane-connect (R18 - S18 - Q18), instead I played Q18 and White answered with R18.

In the problem position, Katago expects this

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

so Black sacrifices three stones and makes a strong, connected group.

~~Lightvector's position doesn't exist since Black has made an extra move,~~ so I'll remove a few stones

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

lightvector · **#128**

Yep,

jlt · **#129**

Oops sorry, I didn't read your preceding diagram carefully.

jlt · **#130**

Position #69, another elementary shape that I missed. Not really a big mistake but an illustration of the fact that some simple moves are still missing in my brain policy network. Black to play.

Click Here To Show Diagram Code: [go]$$Bc $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . O . . . | $$ | . . . . . . . . . . . . . X X O . O . | $$ | . . . X . . . . . , . . . . . X O . . | $$ | . . . . . . . . . . . . . . . X . . . | $$ | . . . . . . . . . . . X X X . . O . . | $$ | . . X O . . . . . . . . O O O . . . . | $$ | . X W X X . . X . . . . . . . . . . . | $$ | X O O . X . . . . . . . . . . . . . . | $$ | X X O O O X . O . , . . . . . , . . . | $$ | . O . . . . O O X . . X O . . . O . . | $$ | . O O . . O O X . X X O O O . . . . . | $$ | . X . . O . X . X . X O O X . . . . . | $$ | . . X X X . . . . X O X X X . O O . . | $$ | . X O O . . . . . X O O O X . O X . . | $$ | . . X O . O X X . , . O X O O , X . . | $$ | . . X O . X O O X X . O X X X X . . . | $$ | . . X X O O . . O O . O . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Answer:

jlt · **#131**

Position #70, Black to play a good endgame move.

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

Akura · **#132**

jlt · **#133**

EricBackus · **#134**

jlt · **#135**

From my kyu perspective, White would just sacrifice two stones, which is not so big:

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

but the AI thinks it's a wrong sequence for White because the weakness C17 is still there, so the following is a much better move

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

Black cannot cut immediately because White threatens to kill A14 so...

Click Here To Show Diagram Code: [go]$$Bcm11 $$ --------------------------------------- $$ | . . . . . . . . . O X . X . . . . . . | $$ | . . 2 . O . . O X X O X . X . . . . . | $$ | . . . O X O O O O X O O X X . . X X . | $$ | . O O 1 X . . O X O O O . . . X . O . | $$ | . O X X . 3 X X X X . . . . . . . . . | $$ | X X X . O . . . . . . . . . . . O . . | $$ | . O O . O O . 4 . . . . . . . . . . . | $$ | . . . O X X O . X X X . X . . . . . . | $$ | . O O X X . . O O O O X X O . . O . . | $$ | . . X O X W . . . , . O X . . , . . . | $$ | . . X . X W . X O . . O X . . O . . . |[/go]

Now, Black could capture the two marked stones but it's not very big at the moment.

EricBackus · **#136**

jlt wrote:

From my kyu perspective, White would just sacrifice two stones, which is not so big

Yea, it was just bad reading on my part.

jlt · **#137**

Position #71, White to play.

Click Here To Show Diagram Code: [go]$$Wc White to play $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O . O X . . . . . X . O . . . . . | $$ | . O . O . X . X X X . X . O . O O O . | $$ | . O . O . O O O O O O O O X X X X X . | $$ | X O . O . . . X X X . O X . . . . . . | $$ | . X O O . X . X O X X O . X . . . X . | $$ | . . X . . . . O O . X O O X . . O X . | $$ | . X . O X . X . O . X X X O O . . O . | $$ | . X X O O . . X O . O O O X . O . . . | $$ | . O O X O X O O O , . . . X . , . . . | $$ | . X . X . O . . . . . . . . . . . . . | $$ | . . X . X . . . . . . . . . X . X . . | $$ | . . . . . . X . . . . . . . . . . X X | $$ | . . . . . . . . . . . . . . . O O O X | $$ | . . . . . . . . . . X . . . . . X O O | $$ | . . . X . . . . . , . . . . O , . . . | $$ | . . . . . X . . . . X . O . . O . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

EricBackus · **#138**

jlt · **#139**

Hint: the last move was

Continue in the area.

Answer:

Shapes to remember (SDK level)

Who is online