Fair komi without ties

[Bill Spight]

I've been thinking that, if the button were to be officially used to fine-tune komi for optimal balance under area scoring (thus inserting 7 komi with button as an additional option between 7.5 komi and 5.5 komi), it would be inconsistent to have it lift ko and superko bans.

Under area scoring the button is a play that gains ½ point. With a single button, unlike a pass, if one player takes the button then the other player cannot, while if one player passes, the other player can. Also, OC, the pass gains nothing. Ing rules consider the pass a play, other rules do not. Scorewise, the button under area scoring is equivalent to this board position under territory scoring (adjusted by komi, OC ).

$$ Territory "button"
$$ ---------------
$$ . . O . . X . .
$$ . . O O O X . .
$$ . . . . . X . .
$$ . . . . . . . .

Click Here To Show Diagram Code

[go]$$ Territory "button"
$$ ---------------
$$ . . O . . X . .
$$ . . O O O X . .
$$ . . . . . X . .
$$ . . . . . . . .[/go]

Where all the stones are alive. Whoever plays here first gains ½ point.

That is, unless a 0-point button with such a capability were used with fractional komi. And, since I see that as an unnecessary complication, I have to see it that way with a half-point button as well...

What do you mean by a 0-point button with such a capability? How is that different from regular area scoring with a 6.5 komi?

[luigi]

What do you mean by a 0-point button with such a capability? How is that different from regular area scoring with a 6.5 komi?

I mean a 0-point button whose only ability is to lift ko and superko bans.

[Bill Spight]

What do you mean by a 0-point button with such a capability? How is that different from regular area scoring with a 6.5 komi?

I mean a 0-point button whose only ability is to lift ko and superko bans.

Well, that wouldn't get you what a button does.

[luigi]

Well, that wouldn't get you what a button does.

Yes, my point is that it would be needed in order to remove the inconsistency between komi 7.5 without button and komi 7 with button. Sometimes optimal on-board scores are different in each case.

[Bill Spight]

Well, that wouldn't get you what a button does.

Yes, my point is that it would be needed in order to remove the inconsistency between komi 7.5 without button and komi 7 with button. Sometimes optimal on-board scores are different in each case.

Well, button go is a hybrid system of both territory and area scoring. The idea is to put a play -- not a pass -- such that it does not normally matter by area scoring who gets the last Japanese dame. You should expect inconsistencies with both area and territory scoring, otherwise it is not a hybrid.

If you implement the button as the first pass and allow two consecutive passes to end play, you add a possible pass fight to a ko fight, a needless complication.

Anyway, Ing rules effectively let a pass lift ko bans. Ing abandoned the original idea of superko, but a superko rule will work with the rest of the Ing rules.

[luigi]

If you implement the button as the first pass and allow two consecutive passes to end play, you add a possible pass fight to a ko fight, a needless complication.

Well, my idea was to make the button neither a pass nor a play. Anyway, do you have an example of such a pass fight?

[Bill Spight]

If you implement the button as the first pass and allow two consecutive passes to end play, you add a possible pass fight to a ko fight, a needless complication.

Well, my idea was to make the button neither a pass nor a play.

How so? What difference would that make? How would it work?

[luigi]

Well, my idea was to make the button neither a pass nor a play.

How so? What difference would that make? How would it work?

The idea is to consider Button Go a way to fine-tune komi under area scoring rather than a compromise between area and territory scoring. This seems especially relevant now that AlphaGo says that the best komi value under area scoring (7.5) gives Black a sizeable advantage (55% win rate).

Because of this, komi 7 with button seems the best alternative, but ideally the adoption of this solution should be made in a way that optimal on-board scores (prior to adding komi and button) don't change. If the button lifts ko and superko bans, some positions yield a different on-board score than regular area scoring, so I'm arguing that maybe it shouldn't have that ability in order for the game to remain one and the same at its core, and in order for "komi 7 plus button" to be considered a legitimate komi for area scoring rather than a Go variant.

That's what I mean by the button not being a play: it's not taken into account by positional superko, whose concern is the board position, i.e. plays. But, of course, it's still not a pass: passing after the opponent takes the button doesn't end the game.

[Bill Spight]

Well, my idea was to make the button neither a pass nor a play.

How so? What difference would that make? How would it work?

That's what I mean by the button not being a play: it's not taken into account by positional superko, whose concern is the board position, i.e. plays. But, of course, it's still not a pass: passing after the opponent takes the button doesn't end the game.

Perhaps one way of implementing that as a variant of AGA rules without a physical button is this way:

1) use territory counting;
2) play stops after two consecutive passes after the first pass;
3) the player making the first pass does not hand over a pass stone;
4) if the opponent of the player who made the first pass makes the last pass, she does not hand over a pass stone for that pass, either;
5) use 6.5 komi (presently).

With no physical button, just treat the first pass as the button.

[luigi]

If you implement the button as the first pass and allow two consecutive passes to end play, you add a possible pass fight to a ko fight, a needless complication.

Can anyone point me to an example of this? I thought I had understood it, but it was a delusion.

(This and the issue of one-sided dame, discussed before, seem strong arguments against implementing the button as the first pass and allowing two consecutive passes to end play.)

[asura]

@luigi
Maybe this is such a position:
http://www.dgob.de/yabbse/index.php?top ... #msg134089
I am not sure, if it matches exactly your question. But even if it does not, it is a very interesting position, so I post it without checking it. Everyone who is interested in go rules will like the position anyway.

It is about the difference between Ikeda T1 und Ikeda A3 rules.
(BTW to make these rules equivalent you have to change the Ikeda T1 rules, so that the player that passed second and finishes the 'normal' game plays the first move in the encore.)