Stone scoring (group tax)

You make a useful point, but the game-version is actually known as “stone scoring,” not “group tax.”

So when we say “stone scoring” and someone asks for clarification, “connectivity bonus” could clarify at least as well as “group tax” would, since the latter phrase clarifies nothing for anyone who hasn’t already heard of this version of the game.


no ing

only stone score

the object of the game is to get the most stones on the board… that’s it

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the object of the game is to get the most stones on the board

yes, it’s a little lame to fill the board once the game is “over”

but i would prefer that than any other way :slight_smile:

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I’ve been trying to find the article where I read that bots trained up on connectivity-bonus rules (stone scoring) develop a distinctly different style of play than bots trained up on standard rules, but it has been eluding me. Has anyone else read anything about this? Got any pointers?


It helps if you call / search for things with their standard names.


Good point! Thanks.

Quoting from that article:

Maybe we can get OGS to implement these rules. :)




There’s a website where you can play the stone-scoring game against a bot on 9x9 and one smaller-size board, but apparently I didn’t bookmark it. I thought it would be in this thread, but I’m not finding the link on forums at all (and yes, I did search for “group tax” and not just “stone scoring” this time. Anyone know that offhand?



Hmm, I know about SquishyGo:



Hmm, that’s a new one for me. I’ve never seen the term “jungo rule” before, but it looks as if that’s what stone scoring is called in Japanese. Thanks!

I remember the very first time someone talked to me about “group tax”, and it was immediately clear to me what it meant, because we were talking about stone scoring and it made sense to pay a tax of 2 points per group since you need to reserve two spaces per group for eyes.

If it had been called “connectivity bonus” I don’t think I would have been able to guess what it meant. In fact I still don’t get what it could possibly mean. Does it mean you start with a negative score equal to minus two times the number of stones you have on the board, and then you get a “connectivity bonus” of two points for every pair of stones which are connected? This sounds impossibly complex.


It just means that you get an extra two points on the score difference every time you manage to split one of your opponent’s groups into two groups. So, a bonus for cutting. Contrariwise, you suffer a two point penalty everytime you allow your opponent to cut one of your groups in two. It refers to the actual game play, which “group tax” completely does not.

My experience was opposite to yours. When I started looking into the stone-scoring game, I found the notion of a group tax completely opaque and unenlightening: it only confused me more. But that’s what everyone calls it!

A bonus for cutting which would be called “connectivity bonus”? Shouldn’t it be “cutting bonus” instead?

Also, a bit counterintuitive in my opinion: I would get points for cutting, rather than my opponent losing points for each group? But that’s not what actually happens. With stone scoring you pay a tax of 2 points on the territory of each group that needs two eyes.

And what happens if my opponent plays Q4 then D16 as their first two moves? Then my opponent begins with two groups on the board, even though I never got to split a group into two.

Yes, exactly. You made a great argument for calling it “group penalty”. Or any other synonym of penalty.

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Indeed although it should push your opponent to take the other splitted 2.

It’s the same thing. If you split an opponent’s group into two, then either your opponent needs to make two more eyes to keep both groups alive, or else one of the groups dies. So you get a bonus two points minimum for cutting. You could think of it as a connectivity bonus too, for the other player, if you prefer thinking in terms of defense rather than attack. But it’s just two sides of the same coin. My point is, the terminology I find less confusing emphasizes the action of the game and not the static array.

Just because your opponent starts out at Q4 and D16 doesn’t mean your opponent won’t be able to connect those two into one group if you do nothing to prevent it. If there’s a distinction here that you’re drawing, I’m not seeing it.