October 9 endgame problem

[Bill Spight]

(;SZ[19]ST[2]GM[1]FF[4]AP[GOWrite:2.2.21]CA[ISO8859-1]AW[ib][cb][ca][ac][bc][cd][be][dd][ed][fd][gd][gc][gb][hc]AB[ab][bb][cc][dc][db][ec][fc][fb][ga][ha][hb][ic][jb][kc][nc][id][hd]PW[ ]GN[ ]PM[2]PB[ ]FG[259:]
)

What is best play for both sides?

How much does gote or reverse sente gain?

Enjoy!

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Edit: For those who prefer diagrams:

$$
$$ ---------------------------------------
$$ | . . O . . . X X . . . . . . . . . . . |
$$ | X X O X . X O X O X . . . . . . . . . |
$$ | O O X X X X O O X . X . . X . . . . . |
$$ | . . O O O O O X X , . . . . . , . . . |
$$ | . O . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |

Click Here To Show Diagram Code

[go]$$
$$ ---------------------------------------
$$ | . . O . . . X X . . . . . . . . . . . |
$$ | X X O X . X O X O X . . . . . . . . . |
$$ | O O X X X X O O X . X . . X . . . . . |
$$ | . . O O O O O X X , . . . . . , . . . |
$$ | . O . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |[/go]

[Loons]

I don't know anything about endgame. I drew this. Is it the answer ?

tree.jpg (25.82 KiB) Viewed 6302 times

Oh, I get it. I have described the question, not the answer.

[illluck]

D19 best for black, E19 best for white I think. 14 points double-gote?

Edit: Ah, black will let white capture the three stones and take corner (but E19 still a bit better than just capturing corner), so 11.5 double-gote?

Edit 2: Ok, now I'm just confused XD Edit 1 is wrong, because black will first capture the two white stones before giving up the three stones (wE19 bD19 wF19 bE18 wF19 bB19 wJ19), and at the end K19 is white's sente. So it seems like that sequence is 11 points double-gote?

[Jordus]

D19 for Black

E19 for white... Best to take the corner

I originally said A19 or B19 for white but found that was small once I played it out....

[emeraldemon]

I agree with illuck's analysis, I think it's 11 pts gote (i.e. 5.5 points miai count). Here's the sequence

$$W
$$ ---------------------------------------
$$ | . . O 2 1 3 X X . . . . . . . . . . . |
$$ | X X O X 4 X O X O X . . . . . . . . . |
$$ | O O X X X X O O X . X . . X . . . . . |
$$ | . . O O O O O X X , . . . . . , . . . |
$$ | . O . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |

Click Here To Show Diagram Code

[go]$$W
$$ ---------------------------------------
$$ | . . O 2 1 3 X X . . . . . . . . . . . |
$$ | X X O X 4 X O X O X . . . . . . . . . |
$$ | O O X X X X O O X . X . . X . . . . . |
$$ | . . O O O O O X X , . . . . . , . . . |
$$ | . O . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |[/go]

$$W
$$ ---------------------------------------
$$ | . 6 O X . 5 X X 7 . . . . . . . . . . |
$$ | X X O X X X O X O X . . . . . . . . . |
$$ | O O X X X X O O X . X . . X . . . . . |
$$ | . . O O O O O X X , . . . . . , . . . |
$$ | . O . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |

Click Here To Show Diagram Code

[go]$$W
$$ ---------------------------------------
$$ | . 6 O X . 5 X X 7 . . . . . . . . . . |
$$ | X X O X X X O X O X . . . . . . . . . |
$$ | O O X X X X O O X . X . . X . . . . . |
$$ | . . O O O O O X X , . . . . . , . . . |
$$ | . O . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |[/go]

$$
$$ ---------------------------------------
$$ | . X . X . O . . O . . . . . . . . . . |
$$ | X X . X X X O . O X . . . . . . . . . |
$$ | O O X X X X O O X . X . . X . . . . . |
$$ | . . O O O O O X X , . . . . . , . . . |
$$ | . O . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |

Click Here To Show Diagram Code

[go]$$
$$ ---------------------------------------
$$ | . X . X . O . . O . . . . . . . . . . |
$$ | X X . X X X O . O X . . . . . . . . . |
$$ | O O X X X X O O X . X . . X . . . . . |
$$ | . . O O O O O X X , . . . . . , . . . |
$$ | . O . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |[/go]

After this, black has 3 points territory and 4 captures = 7
white has 2 points territory and 3 captures = 5, net B+2.

compare with:

$$B
$$ ---------------------------------------
$$ | . . O 1 . . X X s s . . . . . . . . . |
$$ | X X O X . X O X O X . . . . . . . . . |
$$ | O O X X X X O O X . X . . X . . . . . |
$$ | . . O O O O O X X , . . . . . , . . . |
$$ | . O . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |

Click Here To Show Diagram Code

[go]$$B
$$ ---------------------------------------
$$ | . . O 1 . . X X s s . . . . . . . . . |
$$ | X X O X . X O X O X . . . . . . . . . |
$$ | O O X X X X O O X . X . . X . . . . . |
$$ | . . O O O O O X X , . . . . . , . . . |
$$ | . O . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |[/go]

Now black has 3 captures and 10 points (incl. marked) for B+13. Difference is 11. Of course, that whole exchange may not be sente, but where would white tennuki?

[Darrell]

I also agreed with illuck's sequence, but as illuck points out, white has a 1-point sente move to make at the end, so I think it is 12 points gote.

[Bill Spight]

Good going, guys!

(;CA[ISO8859-1]SZ[19]GM[1]AP[GOWrite:2.2.21]ST[2]FF[4]PB[ ]FG[259:]PM[2]AB[bb][dc][cc][fc][ab][ec][id][ga][hd][ha][jb][hb][fb][db][kc][nc][ic]PW[ ]AW[cd][cb][ca][ed][dd][gd][fd][bc][ac][ib][gb][be][gc][hc]GN[ ]
(
;C[In the marked regions Black has 20 points.]B[da]CR[aa][ba][ca][cb][ea][fa][eb][ib][ia][ja][ka][kb][jc][la][lb][ma][mb]
)
(
;C[Tesuji.]W[ea]
(
;B[fa]
;W[da]
;B[ia]
;W[ba]
;B[eb]
;C[In the marked regions, counting captures, Black has 10 points and White has 4 points, for a net of 6 points for Black. But Black can do better.]CR[ab][bb][ib][ja][ka][la][ma][mb][lb][kb][jc]W[aa]
)
(
;C[Corre]B[da]
;C[Tesuji.]W[fa]
;B[eb]
;C[Black cannot capture this stone, because of snapback.]W[fa]
;B[ba]
;W[ia]
;B[tt]
;C[White sente.]W[ja]
;C[Including captives, in the marked regions Black has 13 points and White has 5 points, for a net of 8 points for Black.]B[ka]CR[aa][ca][cb][ha][hb][jc][kb][la][lb][ma][mb]
)

)

)

This is gote.

In the marked regions, the original position is worth 14 points for Black. Each gote gains 6 points.