Are There Legitimate Reasons To Choose New Zealand Over Chinese?

I certainly think so. I’m curious if anybody out there has any additional thoughts on the subject?

There are a couple of aspects of New Zealand rules which are not implemented on OGS. So I will only speak to the parts which do manifest in OGS based games. @GlacialNoivern and I have been playing with it in our own games for a good six months. Before that, our games were 99% Chinese. Chinese has been our favorite ruleset, hands down.

Upon learning about the difference between Positional (Chinese) and Situational (NZ) Superko, it intrigued us to look further. SSK based situations are going to be a super rare occurrence, but the possibility represents one additional micro layer of strategy. After learning about the situations where Suicide would matter, it opened up another micro layer of strategy. For reference: Positions With A Good Suicide and Suicidal Tendencies.

Finally, regarding Handicap, under Chinese rules Black gives White compensation for handicap stones, so that the area which they occupy is not counted. Where (N = number of stone handicap) N stones are given, N÷2 is added to White’s score and N÷2 is subtracted from Black’s score. Under New Zealand rules, no such compensation is given.

The effect of this is that an N stone handicap under New Zealand rules is N points larger than under Chinese rules. Under NZ, White passes the first N-1 moves and Komi is not to be used. Though, OGS does implement a 0.5 Komi in handicap matches to ensure that ties are not possible.

It has been our experience that in NZ handicap games, fewer stones are generally used, since NZ based Handicaps result in a bigger point advantage. Stones also change the tactical and strategic options present on the board. We think the fewer stones on the board in a Handicap match, the better. In our minds, we are playing with Chinese rules, but with a slightly better approach to Handicap games, as well as a couple additional micro layers of potential strategy added into the mix :hugs:


I am in favour of integer komi, but am not so enthusiastic about suicide.

I think if I were to favour a particular ruleset, it would be if AGA were to adjust to an integer komi of 7. This would be very close to ideal, I believe.


What about suicide leads you to desire keeping it out of a game?


Why are AGA rules ideal to you??

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Any superko or beneficial suicide situations are quite rare. While these decisions do theoretically change the game, the specific choice of whether to use PSK or SSK very rarely has practical impact.

The superko rule (in rules like Chinese or AGA) is sometimes even ignored or modified in practice (in over the board play). I’ve read online that triple ko situations have even been ruled as no result or draw in tournaments that are supposedly following Chinese or AGA rules.

I think you make an interesting point about handicap stones having a slightly stronger impact in NZ rules vs Chinese rules. Perhaps that could be viewed as beneficial in requiring one fewer stone in large handicap games. However, it could also be viewed as a drawback in how it would interact with a rating system. This difference could even be a small avenue for rating system abuse.

I believe, when playing a ranked game with automatic handicap, the OGS system will simply assign the same number of handicap stones for both NZ and Chinese rules, and also interprets the handicap advantage as being equivalent (between the two rules sets) when making rating adjustments. However, under NZ rules, black is actually getting a slightly larger advantage. Scoring with handicap under Chinese rules makes the scoring behave closer to Japanese rules, which makes those two rules more compatible (when mixed within the same ratings system) than NZ rules would be.


I remember us talking about this previously and I had performed a test. I deliberately assigned a handicap value though. Perhaps my findings there show that auto-handicap is different? I’m running out the door, so I don’t have time to test right now :frowning_face:. But here is the relevant excerpt; food for thought (source):

New Zealand rules do not award any point compensation for Handicap stones. For comparison, under Chinese rules Black gives White compensation for handicap stones, so that the area which they occupy is not counted. But under NZ rules, no such compensation is given. The rules also specifically state that Komi is not to be used.

To test this I played a match and gave Black 10 handicap stones.The final score for White reflects that no points were added to White’s score to account for handicap stones. However, if you mouse over the Captures text for White, you will see that it says it awards 10 points for Handicap. Despite it showing this, no points are actually reflected in the scoring.

This Handicap data is shown for all OGS games, despite what ruleset being utilized. However, White is afforded 0.5 Komi. I realize that this was done specifically to avoid ties on OGS, but it is worth mentioning as it deviates from the No Komi NZ rule specification for handicap matches.


Interesting, so it seems that OGS (correctly) does not apply any compensation for handicap stones in NZ rules games, yet there is a display bug that erroneously says that compensation has been given.

However, that was not my point. The issue is that (as far as I’m assuming) the rating system treats games under all of the different rules identically, but between the different rules sets, handicap stones may have differing degrees of effectiveness. In isolation, it’s okay for different rules sets to handle handicap differently, but when multiple rules sets are combined under that same rating system, these differences could be a minor problem.

If playing a ranked handicap game, the weaker player should prefer NZ rules and the stronger one should prefer Chinese rules, if they are concerned about rating impact.


:scream: That is a beautiful catch yebellz :nerd_face:. Seriously, high five! :face_with_monocle:


Now if we could just get someone to add a little tooltip next to the box on the create game dialogue…

:roll_eyes: (← :pray: praying for a miracle)

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I find it unintuitive, and to me feels unnatural. I see it as a technical abuse of the liberties rule, rather than a legitimate element of the game.

Philosophically I prefer area scoring, practically I prefer territory counting, and I find a beautiful simplicity in the genius of bringing the two together by making a “pass” literally pass a stone.


I usually play NZ/TT rules with pass stones. I treat it as a “counting trick” rather than an inherent part of the rules, similar to rearranging groups into rectangles at the end.


I feel dense, but I don’t understand how you’re involving the stones. Can you elaborate?

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passing stones is a way you can use territory scoring to get the same result as area scoring. Which is great if you’re not used to area scoring but like it in theory


In the context of using them with NZ/TT though, what is the effect? With AGA it is to allow either Japanese or Chinese counting, but arriving at the same score. So are we talking about NZ/TT with Japanese Counting applied?

If it’s area scoring (and correct me if I’m wrong, but I’m fairly sure it is), it should still come out as the same result so long as you make sure w passes last.


I’d like to make a comment about the phrases “positional superko” and “situational superko.”

I like the terminology that comes from the rules of chess regarding repetition of position. Applying that to go, “positional superko” would become “static superko” and “situational superko” would become “dynamic superko.”

Just a thought. “Positional Superko” and “Situational Superko” are already accepted and understood.

NZ/TT rules use area scoring. However, if you introduce passing stones (i.e. give your opponent a prisoner every time you pass) and have white pass last, then you can use territory counting, which is faster to do.*

*You fill in prisoners and count only surrounded empty territory. Because of the passing stones, the result will be the same as if you used area counting, which may differ from territory counting without passing stones.
This is called . Some rulesets (AGA) explicitly mention it, but you can use it with any area scoring ruleset since you are mathematically guaranteed the same result.


I had no idea that this existed. This is a wonderful article and a very cool option (as NZ and TT are my preferred rulesets). Thank you very much for sharing this :smiley:

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Forgive my ignorance, but when you all say NZTT, what’s the TT part stand for?

Tromp Taylor rules, which are quite similar


From the official rules:

These are essentially the New Zealand rules, re-worded to be as simple and elegant as possible. The NZ rules are in turn the simplest version of Chinese-style rules around. The NZ rules are worded with definitions given recursively, which is elegant and a joy to computer scientists, logicians and mathematicians, but perhaps not so nice for most others. John Tromp came up with the key idea of a stone “seeing” (or as I’ve presently worded “reaching”) a different color. This was the brilliant step which enabled such succinct rules. My modest contribution was the wording for the end-of-game criterion, and putting an expansion into a second tier of interpretations rather than rules. This was

  1. to keep the logical rules as simple as possible, and
  2. to keep things close to how the game is actually played by humans.

And a fun fact about OGS’s implementation of New Zealand rules:



Yes… of course… thank you :smile:

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