9 stone handicap against a player of similar strenght

betoacosta · #1

After losing so many 9 stone games, and being still distant from a position where I can give 9 stones regularly I was wondering. If you play against someone your own rank, how many points do you think you will need to make the game "even"? I remember hearing a rule 1 stone = 10 points but not sure how accurate it is. Has anyone ever tried this?

EdLee · #2

Hi betoacosta,

You must play each person sufficient games to find out empirically.

The distance between two particular individuals is unique;
this is true in Go and is also well known in the martial arts for millennia.

Sennahoj · #3

EdLee wrote:

You must play each person sufficient games to find out empirically.

That's not very helpful, but here is way to understand the question which might be harder for EdLee to deflect in the same way: if two randomly selected played of similar strength (according to some measure) played each other, what is the average realised score difference (after performing that experiment many times)?

To answer your question though, I have no idea beyond that same 1 stone = 10 stone heuristic (but I guess at least for the first stone, it should be more like 1 stone = 6 or 7 points, since that is the usual komi).

DrStraw · #4

I heard long ago that between two pros of equal strength it should be about 140 points. But as Ed says, between amateurs it is anyone's guess.

EdLee · #5

Sennahoj wrote:

That's not very helpful

What do you mean ? It's the only way to find out.

Your own reply doesn't provide any more info; just less succinct.

Uberdude · #6

Sennahoj wrote:

To answer your question though, I have no idea beyond that same 1 stone = 10 stone heuristic (but I guess at least for the first stone, it should be more like 1 stone = 6 or 7 points, since that is the usual komi).

1 stone is worth twice komi (easy to see if you consider black passes for his first move, it goes from black first and white get komi to white first and white gets komi; to balance this back to the original fair position but with colours reversed white would need to lose his komi, and then give another komi to black, a difference of twice komi; so a pass / 1 stone is worth twice komi) so that'd put it more like about 13 points per stone. Also the value of handicap stones is almost certainly not linear, with 9 stones you would probably have a score more than 50% bigger than with 6 stones. But anyway when I (4 dan) play near-beginners at the club on 9 stones and need to work out if they are 25 kyu or 20 kyu I use a rough value of 10 points per stone / rank. So if I beat them on 9 stones by 150 points I estimate them as 150/10 + 9 = 24 ranks weaker than me (so 21k). This is in a fairly competitive game but I won't be going all out to crush them which is why I use the likely underestimate of 10 points (and it makes the arithmetic easier).

Sennahoj · #7

EdLee wrote:

What do you mean ? It's the only way to find out.

That's like saying the only way to find out what komi to use is for every pair of unique players to play against each other lots of times, to calibrate their special komi. Is that how you usually do it?

Sennahoj · #8

Uberdude wrote:

1 stone is worth twice komi (easy to see if you consider black passes for his first move, it goes from black first and white get komi to white first and white gets komi; to balance this back to the original fair position but with colours reversed white would need to lose his komi, and then give another komi to black, a difference of twice komi; so a pass / 1 stone is worth twice komi) so that'd put it more like about 13 points per stone.

hm.. but playing with "one stone handicap" usually means black with no komi right?

Agree about the nonlinearity of course.

EdLee · #9

Sennahoj wrote:

That's like saying the only way to find out what komi to use is for every pair of unique players to play against each other lots of times, to calibrate their special komi.

No, it is not; komi for even games (6.5 in Japan/Korea; 7.5 in China, etc.) is not a magic number pulled out of a hat; it was a result based on thousands of actual pro games, over some span of time; it was determined empirically, and adjusted accordingly, and is still subject to change given new evidence/data.

I don't know if they have the data for other situations:
non-even pro games, or non-19x19 pro games.

As DrStraw says, that's from pro data. If you want to know the same for amateurs, or, for any two particular individuals, you still need to find out empirically.

The fact that you use 6.5/7.5 komi with your friends or other opponents today is because the emprical work had already been done for you by the pros.
And for most of us, we just rely on their results.

But if you have a particular friend, Joe, and you still want to know what is the unique distance between you two, you still have to find it out empirically, whether it's 6.5, 7.5, or something else.

To answer your last question: yes, it has occurred numerous times at our local club. Some members enjoy various types of handicaps; and if they really want to know the answer to the OP's question, they would play many games, over many club meets, to find out the komi between two particular members.

Sennahoj · **#10**

EdLee wrote:

No, it is not; komi for even games (6.5 in Japan/Korea; 7.5 in China, etc.) is not a magic number pulled out of a hat; it was a result based on thousands of actual pro games, over some span of time; it was determined empirically, and adjusted accordingly, and is still subject to change given new evidence/data.

Thanks, I'm aware of this --- and this is exactly how I argue that one could, in principle, determine a fair "9 stone go"-komi.

This is very different from what you seemed to suggest in your original response, namely that the fair number should depend on the particular pair of players, because of martial arts or something.

EdLee · **#11**

Hi Sennahoj,

In the past, unfortunately, I've had a few unpleasant experiences here on the forum and elsewhere online.

It's extremely easy to mis-communicate, even face to face in real life, not to mention online.

I rather we don't start off on the wrong foot.

My original reply to the OP is based on my experiences over the years.
Especially for DDK/SDK levels, the distances vary greatly.
We can rely on some general rule of thumb, yes;
but if the OP sits down with a friend at their Go club,
and they really want to have a fair game,
they need to find out the distance empirically.

xed_over · **#12**

betoacosta wrote:

I remember hearing a rule 1 stone = 10 points but not sure how accurate it is.

yeah, its not accurate, but its a general rule of thumb that works out fairly well.

DrStraw · **#13**

EdLee wrote:

but if the OP sits down with a friend at their Go club,
and they really want to have a fair game,
they need to find out the distance empirically.

When I was learning, long before the days of the internet, we did not think in terms of rank. We all played 3 game kadobans between one another. So I may give one person 3 stones, take 3 from another, but they could be playing at anything from 4 to 8 between them. We had no problem with this as it seems the natural way to play. We rarely played large komi even games but had we done so the same principles would apply.

EdLee · **#14**

DrStraw wrote:

When I was learning, long before the days of the internet, we did not think in terms of rank. We all played 3 game kadobans between one another. So I may give one person 3 stones, take 3 from another, but they could be playing at anything from 4 to 8 between them. We had no problem with this as it seems the natural way to play. We rarely played large komi even games but had we done so the same principles would apply.

Yes, some of our members still regularly enjoy kadobans; others like to experiment with large komis, or other creative handicaps (two moves in a row every four moves, etc.) -- all kinds of interesting variations, and all very much emprical.

RobertJasiek · **#15**

I played quite a few H9 games against players of equal strength. With Japanese handicap, the komi should be about 130. With freely placed handicap, maybe a bit more.

Sennahoj · **#16**

Hey EdLee, I guess I'm sometimes too easily annoyed by what I consider to be overly-philosophical non-answers...

I read back and see that I wrote too sharply, and I apologise for that. No ill will intended.

Of course one can always say that the difference between any two players is unique, but I honestly don't think that's a helpful answer, it's just kind of tautological. It didn't seem like an answer to a generous reading of the question, i.e. trying to give as good meaning to the question as possible.

EdLee · **#17**

Hi Sennahoj,

Sennahoj · **#18**

EdLee, this is thing: it is not hard to take any question about a non-trivial subject and start generating lots and lots of related questions / sub-questions, etc. That is not providing an answer, it's a behaviour that we can call "pretending to be wise", because it can give the appearance of insight / depth, while not doing any actual work.

The most interesting of the questions you generated was "What level of an answer is BC looking for ?", and this is a good question that one should consider before giving a reply. In my judgement (and others), the right level here was "what is fair komi in 9 stone Go?".

Bonobo · **#19**

Sennahoj wrote:

[..] That is not providing an answer, it's a behaviour that we can call "pretending to be wise", because it can give the appearance of insight / depth, while not doing any actual work.

[..]

This I find to be a comment bordering on insult … at least “wiser than thou”.

Sometimes the wisdom of questioning the question won't be recognized because we insist on quick and easy answers.

Yes, there always exist quick, easy, and wrong solutions to any problem.

To me, the replies given by EdLee and others here seem to suggest that the question may be just too imprecise to give a precise answer (actually the setting for the question seems to be too foggy, IMO).

Uberdude · **#20**

But the OP did not ask for a precise answer. In fact he didn't even ask for a truth, just an opinion "If you play against someone your own rank, how many points do you think you will need to make the game "even"? " Thus I think "About 120 points" is a perfectly good answer. I presume the OP is intelligent enough to interpret this sensibly, and not crucify me if he finds one pairing of players for whom the correct komi in a 9h is not 120 points. "120 points with a standard deviation of 30 points for 1kyus and 60 points for 10 kyus and 140 points with a standard deviation of 5 points for 9ps" is good too (though I'm just pulling numbers out of my backside but the principle of higher variation for lower ranks is probably true). It is possible to give helpful, imprecise answers with caveats (either explicitly stated or presumed in the intelligence of the reader).

9 stone handicap against a player of similar strenght

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