An interesting question

General conversations about Go belong here.
Post Reply
Violence
Lives in sente
Posts: 754
Joined: Thu Apr 22, 2010 1:12 am
Rank: Something Dan
GD Posts: 720
Has thanked: 9 times
Been thanked: 144 times

An interesting question

Post by Violence »

Something I thought up while taking a break.

The game is Batoo.

Click Here To Show Diagram Code
[go]$$Wc
$$|-----------|
$$|.....p.....|
$$|...........|
$$|..m.....m..|
$$|...........|
$$|......O....|
$$|p...XOX...p|
$$|....OX.....|
$$|...........|
$$|..m.....m..|
$$|...........|
$$|.....p.....|
$$|-----------|[/go]


The question is... how much komi would you bet, and why?
User avatar
topazg
Tengen
Posts: 4511
Joined: Wed Apr 21, 2010 3:08 am
Rank: Nebulous
GD Posts: 918
KGS: topazg
Location: Chatteris, UK
Has thanked: 1579 times
Been thanked: 650 times
Contact:

Re: An interesting question

Post by topazg »

As Black, 20.
As White, 25 (because I'd bet 20 as Black).

Black playing first seems just huge.
User avatar
Aphelion
Lives in sente
Posts: 766
Joined: Thu Apr 22, 2010 12:14 pm
Rank: KGS 4 kyu
GD Posts: 227
KGS: Aphelion02
Has thanked: 24 times
Been thanked: 59 times

Re: An interesting question

Post by Aphelion »

Maybe 30 points, the value of the ponnuki?
Violence
Lives in sente
Posts: 754
Joined: Thu Apr 22, 2010 1:12 am
Rank: Something Dan
GD Posts: 720
Has thanked: 9 times
Been thanked: 144 times

Re: An interesting question

Post by Violence »

Really!?!

I would bet 50 at the minimum... Maybe 80.

My rationale is that when you take the middle stone, the other two become almost worthless.

It's like black gets to play 4 moves in a row!
lightvector
Lives in sente
Posts: 759
Joined: Sat Jun 19, 2010 10:11 pm
Rank: maybe 2d
GD Posts: 0
Has thanked: 114 times
Been thanked: 916 times

Re: An interesting question

Post by lightvector »

As black, I would probably bet around 35 or so. Maybe slightly more. I'd feel very good about winning by at least that on board if I got to play first, especially since eating those base stones of white is worth (5? 6?) points each, so the two that remain will be an annoying burden for white. And if white outbid me, then I'd also be very happy to play second. It looks like the fight after white connects is unfavorable for black, but it doesn't seem to be 35 points unfavorable. Maybe I'm completely off though.

As white, I think I would cry. If black goes first, he has an overwhelming position on board. If white goes first, white merely has a favorable position on board. So if black uses his bid to split the difference well, white is at a huge disadvantage, regardless of what he does.
User avatar
MountainGo
Lives with ko
Posts: 263
Joined: Tue Apr 20, 2010 9:23 pm
Rank: KGS 5-kyu
GD Posts: 60
Location: Philadelphia, PA
Has thanked: 32 times
Been thanked: 10 times
Contact:

Re: An interesting question

Post by MountainGo »

Black already has an advantage. If Black plays first, Black is monstrously ahead. If White plays first, Black is moderately behind. So Black can be conservative and bet around 25.
User avatar
prokofiev
Lives with ko
Posts: 223
Joined: Tue Apr 27, 2010 8:03 pm
Rank: decent sdk
GD Posts: 138
Has thanked: 67 times
Been thanked: 10 times

Re: An interesting question

Post by prokofiev »

Violence wrote:Really!?!

I would bet 50 at the minimum... Maybe 80.

My rationale is that when you take the middle stone, the other two become almost worthless.

It's like black gets to play 4 moves in a row!


I'm not one to question your judgement, but 80 in particular seems huge. Perhaps you're forgetting to divide by two (komi is half the value of a move)?

Say the ponnuki is worth 30 points. Plus you get a 5 point capture. Plus white made two almost worthless moves (for a loss of at most 15 points each?), and maybe will lose the 5 point bonus for one of them. We're up to 70 now, but it's white's move, so let's subtract 7.5 (let's say 8). So black is maybe up 62 points (small board vagaries not withstanding).

Compare to the alternative of white going first: Let's say black loses one of the 5 point stones, and my guess is white is up not just sente but a full move, so guess another 15 points. That's 20.

So adding those two I can get your 80 (in fact 82) with some plausble but possibly generous estimations, but now we have to divide by two, getting 40 or so.

Caveat: It seems possible that all scores should be reduced somewhat in batoo because of the hidden move, which forces us to play conservatively, so maybe what looks like a 62 point advantage won't actually be convertible to such?
Post Reply