Simultaneous Capture

[Dusk Eagle]

1. I don't understand. I meant that one should not look at any ruleset with the bias that 'it's just a change to one we have already.' Pretend Go doesn't exist yet. Is simcap better?

I think most of the people here have already expressed their opinion that it does not seem better or worse than normal Go.

2. & 3. I suppose there is no best version of Go unless we agree there exists a purpose to Go. I started this thread because I believe we should strive to make Go, a game unique in its simplicity (rules only) yet depth, simpler and deeper. So far, it doesn't seem likely that simcap achieves the latter.

I really don't share your goals, but I don't see how simultaneous capture achieves your goal either. It doesn't seem to me that regular Go is much if at all more complicated than simultaneous capture Go.

If you want to play Go with those rules, I have no objections. However, the response you are getting here is pretty much the same as the response I expect you would get it if you went on a chess forum and suggested changing the rules so that a knight can move one space forward, as long as it is not capturing a piece (like a pawn). Is it demonstrably better or worse? I doubt it. Does it seem to lack a reason to make the change? Yes. We can debate which is better if you can give some good reasons why you think simultaneous capture might be better, but please don't expect us to actually change the basic rules of a game that has been played for thousands of years and is played worldwide.

[Mr. Mormon]

Rules-wise, the only reason simcap is any simpler is because normal capture specifically allows surrounded capturing stones/groups to stay on the board (and we can ignore that prisoner ambiguity with area scoring); not a big thing, or is it? I'm asking what simcap would imply, not for a vote. To recap (no ko intended) from the SL page, points to consider include length of game, involvement of superko, frequency of sekis, difficulty of killing, and number of ko threats necessary to win a ko fight.

[Mr. Mormon]

It seems to me that sekis would be less common because in the most common type, the player with less stones would break it. It would force an area to be re-resolved, lengthening the game, but perhaps making the moves leading to capture boring? Ko might be the only way to make a seki.

[HermanHiddema]

It seems to me that sekis would be less common because in the most common type, the player with less stones would break it. It would force an area to be re-resolved, lengthening the game, but perhaps making the moves leading to capture boring? Ko might be the only way to make a seki.

You would get sekis with a single shared liberty, because neither player is willing to make the capture. Making the capture allows the other player to play first in that area, and probably more points. Example:

$$B
$$ -------------
$$ . X O X X O .
$$ . X O . X O .
$$ . X O O X O .
$$ . X X X O O .

Click Here To Show Diagram Code

[go]$$B
$$ -------------
$$ . X O X X O .
$$ . X O . X O .
$$ . X O O X O .
$$ . X X X O O .[/go]

It does not matter who simul-captures, the resulting position will be the same:

$$B
$$ -------------
$$ . X . . . O .
$$ . X . a . O .
$$ . X . . . O .
$$ . X X X O O .

Click Here To Show Diagram Code

[go]$$B
$$ -------------
$$ . X . . . O .
$$ . X . a . O .
$$ . X . . . O .
$$ . X X X O O .[/go]

In this position, it is obvious that the player who gets to play at a will be better off locally.

Therefore, neither player is willing to capture in the original diagram.

[Mr. Mormon]

I never thought of that. Would snapback be more likely to involve ko?

[HermanHiddema]

I never thought of that. Would snapback be more likely to involve ko?

What do you mean?

Snapback example:

$$B
$$ . . . . . .
$$ . . O O O .
$$ O O . X O .
$$ X X O X O .
$$ . X X O O .
$$ . . . X X .
$$ . . X . . .

Click Here To Show Diagram Code

[go]$$B
$$ . . . . . .
$$ . . O O O .
$$ O O . X O .
$$ X X O X O .
$$ . X X O O .
$$ . . . X X .
$$ . . X . . .[/go]

Suppose black captures:

$$B
$$ . . . . . .
$$ . . O O O .
$$ O O 1 X O .
$$ X X O X O .
$$ . X X O O .
$$ . . . X X .
$$ . . X . . .

Click Here To Show Diagram Code

[go]$$B
$$ . . . . . .
$$ . . O O O .
$$ O O 1 X O .
$$ X X O X O .
$$ . X X O O .
$$ . . . X X .
$$ . . X . . .[/go]

Both the black and the white stones disappear.

Then white can take the territory:

$$B
$$ . . . . . .
$$ . . O O O .
$$ O O . . O .
$$ X X 2 . O .
$$ . X X O O .
$$ . . . X X .
$$ . . X . . .

Click Here To Show Diagram Code

[go]$$B
$$ . . . . . .
$$ . . O O O .
$$ O O . . O .
$$ X X 2 . O .
$$ . X X O O .
$$ . . . X X .
$$ . . X . . .[/go]

There is relatively little difference with snapback's in normal go, as the end position is the same if and are played like this. The moment the black stones are taken off just changes, which changes the size of the plays, and white can choose to ignore more easily.

[tromp]

What do you think about this modification to the capture rule?

From a graph theoretic viewpoint, it destroys the nice property that a
game of Go corresponds to a simple path through the graph of all legal positions.

For example, on a 2x2 board the following simulcap
games correspond to the same simple path:

A1 A2 B1 B2 pass pass
A1 A2 B1 pass B2 pass pass

regards,
-John

[badukJr]

It seems to me that sekis would be less common because in the most common type, the player with less stones would break it. It would force an area to be re-resolved, lengthening the game, but perhaps making the moves leading to capture boring? Ko might be the only way to make a seki.

You would get sekis with a single shared liberty, because neither player is willing to make the capture. Making the capture allows the other player to play first in that area, and probably more points. Example:

$$B
$$ -------------
$$ . X O X X O .
$$ . X O . X O .
$$ . X O O X O .
$$ . X X X O O .

Click Here To Show Diagram Code

[go]$$B
$$ -------------
$$ . X O X X O .
$$ . X O . X O .
$$ . X O O X O .
$$ . X X X O O .[/go]

It does not matter who simul-captures, the resulting position will be the same:

$$B
$$ -------------
$$ . X . . . O .
$$ . X . a . O .
$$ . X . . . O .
$$ . X X X O O .

Click Here To Show Diagram Code

[go]$$B
$$ -------------
$$ . X . . . O .
$$ . X . a . O .
$$ . X . . . O .
$$ . X X X O O .[/go]

In this position, it is obvious that the player who gets to play at a will be better off locally.

Therefore, neither player is willing to capture in the original diagram.

How common is seki with same number of stones? If one has many less stones in the seki, he would want to break it. Then you get a bizarre dame filling area.

Corners would be a lot different too. But why take the time to study it when I could study the real game?