Simultaneous Capture


MrMormon: Copied from Alter Igo:

 Immediately after each stone is placed, every string that
 is not adjacent to at least one empty intersection, is
 removed from the board.

This rule is simpler than the traditional rule of capture, yet I wonder if it would make a deeper game. Games would be longer because of the increased number of captured stones. Superko would be more involved. Basic ko wouldn't work the same way. Would seki be impossible, and is that a good thing? Would killing be too easy? Is it worth making a server to try it out?

willemien I think it is just allowing suicide (also for single stones?) seki's are still possible. (the reasons why seki's exist are 1) you cannot put the opponent in atari without putting yourself in atari as well (auto atari) 2) if you capture the opponents stones you are left with only one eye. and die because of that. (Maybe there are others but i cannot think of one at the moment) The rule affects neither, so why would this rule eliminate them ?

tapir: You would have several new killing shapes (nakade) to make and the status of a lot of basic formations will change. E.g. all those forms which squeeze two stones on two 1-2 points will be dead. Seki will still exist, though in eyeless seki both players can choose mutual death instead of mutual life (different number of stones in the seki, or the territory underneath preferring one player may make one of them choose mutual death). Ko won't function differently but not at all. In short, it is a different game.

MrMormon: I assume you mean basic ko. It's still there; it just takes two ko threats and moves instead of one to 'recapture'.

willemien: maybe i misunderstood the whole idea of Simultaneous Capture

Do you mean something like:

White's Move  

it surely makes a different game. need to think about it :)

MrMormon: Apparently [ext] Tromp and [ext] Taylor did.

[ext] Original Usenet thread

MrMormon: I reference this page on Life in 19x19 at [ext]

Diagrams from the discussion

John Tromp's ko sequence


B1 starts a ko; W2 ko threat; B3 answers threat; W4 takes back; B5 makes a threat, etc.

Bill Taylor's "little oddities" (corrected second day posts)

White is ALIVE in standard go, but DEAD in SimKill go.  

Could someone explain how this is dead? Dave


Edit Dave: OK, I get it...

White is DEAD.  

Dave: It looks like White is alive in seki. In order to kill, Black has to fill in all around before filling the last liberty for both Black and White. So we get this...

White is DEAD.  

Should Black capture, White gets 12 Black stones in exchange for 8 White ones. What have I got wrong here?

Edit Dave: OK, I think I get it...

White is DEAD.  

Black ends up minus four points on captured stones but with 20 points of territory here.

Simultaneous Capture last edited by DaveSigaty on June 8, 2011 - 09:20
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