Life In 19x19

http://www.pandanet.co.jp/event/13ro_to ... ndex_e.htm

The handicap system (-3 komi per 1/2 rank difference) is designed to let the weakest player win but the even game 6.5 komi is really dubious. It should be 8.5. 6.5 looks like "We use it 19x19, so let's try it for 13x13, too.". Komi should have justification. I see none for 6.5 for 13x13. 8.5 has the good justification of many close games in European 13x13 Championships.

Do you have statistics to support your claim?

RobertJasiek wrote:8.5 has the good justification of many close games in European 13x13 Championships.

Do you have statistics for the score difference on 13x13 at the EGC?

I do not have formal statistics but from 1993 to 2014 I attended each European (Congress) 13x13 Championship and played / watched preliminaries and finals to the final games. Almost all years used 8.5 komi. In evenly ranked games (kibitzed or my own), 0.5 scores have been frequent and, to the best of my memory, the mean and peak of close scores (neither Black nor White was preferred).

How about the claim that 6 points per rank (3 points per half rank) is to the advantage of the weaker player? Do you have numbers for that?

The EGC uses roughly 3.5 points per rank and sees white win much more often, so that would be too little. Also given that a player gets roughly 14 points per rank on 19x19, 6 doesn't sound so bad on 13x13.

6.5 has been fairly commonly used lately in Japan for the 13x13 crowdfunding event and the computer-human matches. No one has seemed unhappy with it.

HermanHiddema wrote:How about the claim that 6 points per rank (3 points per half rank) is to the advantage of the weaker player? Do you have numbers for that?

1) Typical per rank komi increments in 13x13 EGCs have been 2 or sometimes 3, and this has turned out to be reasonable. (Needless to say, weak players not thinking at all need more komi per rank. The 2 or 3 komi per rank is fair in matches in which both the stronger and the weaker players think well about their moves.)

2) An increment of 6 komi per rank on 13x13 very quickly leads to so many komi that the simplest opening strategies followed by dull, but blunder-free, play by Black are good enough to win. Any significantly weaker player should be able to win with "take territory early, then just connect your important stones and block your already existing territories" as his strategy.

The EGC uses roughly 3.5 points per rank

We are not speaking about 19x19. 19x19 has 361 intersections, 13x13 has 169 intersections. To compare komi increments approximately, multiply by 169/361.

and sees white win much more often,

Is this a 19x19 even game statistics for all ranks? If so, it shows that weak black players do not always know how to use their advantage of starting well. This says very little for 13x13.

so that would be too little. Also given that a player gets roughly 14 points per rank on 19x19,

Rank-handicap-komi relations are not sufficiently reliable for high handicaps to make such statements, IMO.

6 doesn't sound so bad on 13x13.

You miss the special properties of the 13x13 board: its size favours fighting / exchange strategies, which Black can initiate well, and he must if indeed the even game komi is 8.5. 19x19 strategy does not work well on 13x13.

oren wrote:6.5 has been fairly commonly used lately in Japan for the 13x13 crowdfunding event and the computer-human matches. No one has seemed unhappy with it.

Interesting. Where can we read more about those events?

Now I would like to know whether, on average in such 6.5 komi 13x13 tournaments, Black did use his first move advantage fully by using fighting / exchange strategies or whether Black would play too cautiously as if it were a 19x19 game. The wrong komi can motivate the wrong strategies and thus close games with many 0.5 results for the wrong reasons. I am not conconvinced by such results until I see Black fighting / exchanging properly in many of the 13x13 games.

Have they also tried many 8.5 komi games? They should to find out the best komi. Otherwise, it is like decades of the wrong 5.5 komi on the 19x19 board: the wrong komi encourages the wrong strategies and we get misleading statistics.

RobertJasiek wrote:We are not speaking about 19x19. 19x19 has 361 intersections, 13x13 has 169 intersections. To compare komi increments approximately, multiply by 169/361.

It seems problematic to assume that komi is proportional to board size, unless you think that correct komi for a 9x9 is about 1.5? If nothing else, I suspect that komi is also proportional to the number of moves to be expected in a game, since the first move out of 40 or 50 should be much more important proportionally than the first out of 250.

If you're referring to the idea that the change is komi for one (19x19) stone's difference in ranks should be set proportionally, this seems more reasonable, but it still breaks down for smaller solvable boards, I believe.

RobertJasiek wrote:

HermanHiddema wrote:How about the claim that 6 points per rank (3 points per half rank) is to the advantage of the weaker player? Do you have numbers for that?

1) Typical per rank komi increments in 13x13 EGCs have been 2 or sometimes 3, and this has turned out to be reasonable. (Needless to say, weak players not thinking at all need more komi per rank. The 2 or 3 komi per rank is fair in matches in which both the stronger and the weaker players think well about their moves.)

According to sensei's library, it is more like 3.5

2) An increment of 6 komi per rank on 13x13 very quickly leads to so many komi that the simplest opening strategies followed by dull, but blunder-free, play by Black are good enough to win. Any significantly weaker player should be able to win with "take territory early, then just connect your important stones and block your already existing territories" as his strategy.

The EGC uses roughly 3.5 points per rank

We are not speaking about 19x19. 19x19 has 361 intersections, 13x13 has 169 intersections. To compare komi increments approximately, multiply by 169/361.

No, I am talking about 13x13. 19x19 uses 14 points per rank. Multiplying that by 169/361 suggests 6.5 for 13x13

and sees white win much more often,

Is this a 19x19 even game statistics for all ranks? If so, it shows that weak black players do not always know how to use their advantage of starting well. This says very little for 13x13.

No, it is 13x13. And black not knowing how to use their handicap/komi advantage is exactly why they get handicap/komi. They are weaker players.

There's a list of statistics from the 2010 EGC at http://senseis.xmp.net/?HandicapForSmal ... Sizes#toc5

so that would be too little. Also given that a player gets roughly 14 points per rank on 19x19,

Rank-handicap-komi relations are not sufficiently reliable for high handicaps to make such statements, IMO.

Not for high handicaps, no, but the first few stones will not be far off. And the maximum rank difference at this event will be around 7 stones in A class.

RobertJasiek wrote:Have they also tried many 8.5 komi games? They should to find out the best komi. Otherwise, it is like decades of the wrong 5.5 komi on the 19x19 board: the wrong komi encourages the wrong strategies and we get misleading statistics.

No. They're playing with 6.5 now. Maybe in the future if black can win significantly more, it would change.

HermanHiddema wrote:According to sensei's library, it is more like 3.5

Which Sensei's pages, how do you conclude from them that they are saying exactly this?

19x19 uses 14 points per rank. Multiplying that by 169/361 suggests 6.5 for 13x13

Exactly that's what I and skydyr and trying to say: one must not simply try to derive the komi of one board size to another board size because proportionality is not ensured.

And black not knowing how to use their handicap/komi advantage is exactly why they get handicap/komi. They are weaker players.

You are not understanding what I have been writing: WRT to correct even game komi, I do not speak of the handicap system - I speak of the even game 13x13 komi! In even games, there is no weaker player in terms of ranks!

There's a list of statistics from the 2010 EGC at http://senseis.xmp.net/?HandicapForSmal ... Sizes#toc5

These statistics say essentially nothing about even games 13x13 because these statistics are for all played games, including the handicap games.

RobertJasiek wrote:

HermanHiddema wrote:According to sensei's library, it is more like 3.5

Which Sensei's pages, how do you conclude from them that they are saying exactly this?

The same one I linked earlier, http://senseis.xmp.net/?HandicapForSmal ... Sizes#toc5

The system there gives 1 handicap every five ranks. If 8.5 is an accurate komi, then the value of the first move is around 17 and the first few handicap stones will have a similar value. 17/5 = 3.4 which is where I get the "roughly 3.5" from.

19x19 uses 14 points per rank. Multiplying that by 169/361 suggests 6.5 for 13x13

Exactly that's what I and skydyr and trying to say: one must not simply try to derive the komi of one board size to another board size because proportionality is not ensured.

It seems you are confused between "what is appropriate even game komi for 13x13" and "what is an appropriate komi increment per rank for 13x13 handicaps"

You said: "We are not speaking about 19x19. 19x19 has 361 intersections, 13x13 has 169 intersections. To compare komi increments approximately, multiply by 169/361.". So it was you who suggested this method for calculating komi increments. I simply applied it and got a value of 6.5. Note that this is not "even game komi 6.5" but "komi increment per rank 6.5"

And black not knowing how to use their handicap/komi advantage is exactly why they get handicap/komi. They are weaker players.

You are not understanding what I have been writing: WRT to correct even game komi, I do not speak of the handicap system - I speak of the even game 13x13 komi! In even games, there is no weaker player in terms of ranks!

There's a list of statistics from the 2010 EGC at http://senseis.xmp.net/?HandicapForSmal ... Sizes#toc5

These statistics say essentially nothing about even games 13x13 because these statistics are for all played games, including the handicap games.

Again the above two points seem to be confused on the topic, which is "komi increments in handicap games", not "correct komi in even games".

Those statistics show that the EGC komi increment of roughly 3.5 per rank is insufficient to give the weaker players an even chance of winning games.

It was your assertion that 6 points per rank (3 per half rank) would give the weaker player a better than even chance to win. I was asking if you have any numbers to back up that assertion. The only numbers I know of (which I posted) suggest that at least 4 points per rank is required.

HermanHiddema wrote:If 8.5 is an accurate komi, then the value of the first move is around 17

Ok, where you mean the miai value.

and the first few handicap stones will have a similar value. 17/5 = 3.4 which is where I get the "roughly 3.5" from.

Now I understand what you are referring to: you divide by 5 because the referred handicap table adds another handicap stone every 5 ranks. Ok, this makes sense numerically.

Those statistics show that the EGC komi increment of roughly 3.5 per rank is insufficient to give the weaker players an even chance of winning games.

It was your assertion that 6 points per rank (3 per half rank) would give the weaker player a better than even chance to win. I was asking if you have any numbers to back up that assertion. The only numbers I know of (which I posted) suggest that at least 4 points per rank is required.

1) I do not have statistics - I have only much kibitzing and playing.

2) The aforementioned numerical relation does not work well in practice.

3) I have observed when kibitzing and playing 13x13 the following (and similarly 9x9): there are two types of weaker players: a) those applying basic go theory well and having ca. 50% winning chance under the handicap system 1 stone per 5 ranks and else 2 komi decrement per rank versus b) those not applying basic go theory well and needing some greater or much greater handicap to have ca. 50% winning chance. This has consequences for handicap - winning statistics, which indifferently measure both (a) and (b) players: they measure how weak on average the weaker players play instead of measuring how strong the weaker players should play. This is so also because 13x13 tournaments are rare and (b) players get too little motivation to develop a reasonable 13x13 skill. (a) players get their motivation nevertheless from their pride to play well and seriously attempt to win. I recommend the aforementioned handicap system because I want to give roughly equal chances to stronger players and (a) players. A few others suggest greater handicaps because they want to tolerate the average of (a) and (b) players and do not care for equal winning chances for white top players, whose disadvantage is overlooked in the overall averaging statistics.

@Robert: Ok, so your assertion is that the 6 pts komi increase per rank is perhaps not unfair on average for all players, but that there exist weaker players whose playing style is particularly suitable for defending an existing advantage and that such players would be advantaged by this system?

So you initial statement of "The handicap system (-3 komi per 1/2 rank difference) is designed to let the weakest player win..." is perhaps not entirely accurate in that respect. The weakest (or weakest few) players may not possess the appropriate playing style (or may lose to players who are only slightly stronger, because their initial advantage becomes insufficient).

Now an additional complication is, of course, that there is no handicap, only komi. Some players who are particularly skilled at defending a handicap advantage may not be equally skilled at defending a komi advantage.

I guess we'll see what happens. It will be interesting data.

Something like this happened in the 1994 final game of the EGC, IIRC, 13x13 tournament, in which Black was 20k and won the game due to playing out a ladder worse than this example:

Click Here To Show Diagram Code

[go]$$B
$$ +---------------------------+
$$ | . . . . . . . . . . . . . |
$$ | . . . . O O . . . O O . . |
$$ | . . O O X X . . . X O . . |
$$ | . . X X . . X . . X X . . |
$$ | . . . . . . . . . . . . . |
$$ | . . . . O . . . . . . . . |
$$ | . . . X . 6 X . . X . . . |
$$ | . . . . 5 O 4 1 . . . . . |
$$ | . . . . . 3 2 O X X . X . |
$$ | . . . X . . X O O X X O . |
$$ | . . . . . . X . O X O . . |
$$ | . . . . . . . . . O . O . |
$$ | . . . . . . . . . . . . . |
$$ +---------------------------+[/go]

The only reason for the 20k winning the tournament was, OC, a too great handicap.

EDITED