Endgame: Lost Points

quantumf · Post by **quantumf** » Thu Nov 27, 2014 7:10 am

RobertJasiek wrote:quantumf, factor 10 or 20 bears no justification. We need to study interdendencies to assess the extent of double counting.

My estimate of the factor (10 to 20) is as justified as your estimate (1). Yes, we need to study the interdependencies, but that is impossible to do well - every move would have to be compared to every other actual move and every other better move, and also compared to all alternative follow-ups to every move.

Even to do it very badly will be extremely difficult, but we can try, I suppose. Let's pick two moves more or less at random (208 and 218). How would you assess the value of 218 if 208 had been played in the correct place? Would actual 218 even have been an option if 208 had been played correctly?

Don't get me wrong, I'm intrigued by the idea you have proposed, but I'm sceptical of how meaningful it will prove to be. My take on it is that, yes, basically every move has an endgame aspect, but players need to be ready before they play the correct (endgame) move. They need to understand how their choice impacts on the opening, middle game and endgame, and select the right move based on their overall ability - selecting the "correct" move may be catastrophic for them in the middle game if they are unable to deal correctly with the other implications of the move.

quantumf · Post by **quantumf** » Thu Nov 27, 2014 7:14 am

Sennahoj wrote:quantumf, I think 10-20 seems like a too large factor. Simply taking Roberts numbers at face value, his predicted score difference is 237-140=97, which is only a factor 2 or so larger than the actual game.

My alternative estimate was based on the gross value of 237, not the differential. I don't believe any player would have gotten 237 extra points by playing correct endgame. I'm suggesting that perhaps 15 - 30 is more likely, but it's incredibly difficult to make this statement (or any similar statement) in the context of an actual game with lots of other non-endgame stuff also happening.

S2W · Post by **S2W** » Thu Nov 27, 2014 7:26 am

I think Logan's joke post still has a point. It's one thing to declare a loss of x points and another to show it - let's see the variations!

Uberdude · Post by **Uberdude** » Thu Nov 27, 2014 7:27 am

RobertJasiek wrote:By doing only "the endgame", you have studied only part of the game and, particular, overlooked endgame(-like) moves during opening and middle game.

How is this an "endgame-like" move?

Click Here To Show Diagram Code: [go]$$W $$ +---------------------------------------+ $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . 1 . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O , . . . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ +---------------------------------------+[/go]

Also 7 as the points value of this mistake strikes me as maybe too much. There was a series in Go World a while back about "How many points do these mistakes lose", by Ishida 'caluclator' Yoshio iirc, and I remember being struck how surprisingly small they were given there were pretty obvious dumb kyu mistakes. You probably wouldn't like its lack of rigour, but even Ishida's intuition shouldn't be too wrong.

Also you seem to give 7 points as the value of not attacking/defending a weak group. But if you play a perfectly good opening point you don't really lose points, it's more like a missed opportunity to gain more than a fair result from your opponent's mistake. And if your opponent does defend it that won't gain him many points and you get another big opening point and race on ahead. You don't have to chase a weak group to profit from it, merely getting many big moves whilst your opponent plays small moves is another way. Or what if you do attack it the next move after your opponent failed to defend? As far as the end result of the game is concerned the points are the same, but according to you I lost points. This is similar to my 5,5,15,13 example: changing the order of moves which has no net effect on the game score does have an effect on your "endgame points mistake total" score. If you were doing double entry accounting, your books wouldn't balance.

P.S. about my game, it was a long time ago I can't remember it.

Sennahoj · Post by **Sennahoj** » Thu Nov 27, 2014 7:31 am

quantumf: well but it's linear right, any factor you apply to the gross needs to apply to the net....

I also think that the number is too high, but disregarding double counting etc, I think the main reason that it seems so high is that Robert includes lots of moves that people wouldn't usually think of as endgame. It seems likely that a very strong player could win consistently against this White with 100+ points, that could come from attacking at moments early in the game (where Robert credited points for mistakes).

RobertJasiek · Post by **RobertJasiek** » Thu Nov 27, 2014 7:45 am

Uberdude, endgame is concerned with playing the bigger moves. Move 6 plays in the smaller gap and therefore is a smaller move than if played in the wider gap. Since the gaps are of simple nature (one stone at each end of the gap), such a simple consideration of width is valid and good enough to assess that the move is a mistake. Its exact loss value is a matter of further study.

quantumf · Post by **quantumf** » Thu Nov 27, 2014 7:54 am

Sennahoj wrote:quantumf: well but it's linear right, any factor you apply to the gross needs to apply to the net....

I suppose so. I just meant I was only considering the matter of how many extra points a single player could gain.

Sennahoj wrote:I also think that the number is too high, but disregarding double counting etc, I think the main reason that it seems so high is that Robert include lots of moves that people wouldn't usually think of as endgame. It seems likely that a very strong player could win consistently against White with 100+ points, that could come from attacking at moments early in the game (where Robert credited points for mistakes).

Largely agreed. Certainly a strong player wouldn't in general bother about endgame when playing a much weaker player, they'd just crush them in a fight. Having said that, why I think there is something to be said for Robert's idea, when I play slightly stronger players (maybe 3 stones stronger), and particularly when I play teaching games against MUCH stronger players, where they're not trying to crush me as soon as possible, I'm generally struck by how well their early or middle games moves work out when it comes to the end game. Somehow their moves which seemed to only have a meaning in the middle game enable them to consistently get better endgame moves. This is not a coincidence, because I too consciously consider the endgame when I play middle games moves (although I would not make this claim for the opening), it's just that stronger players do it better than me.

HermanHiddema · Post by **HermanHiddema** » Thu Nov 27, 2014 8:14 am

Ok, because the whole methodology is interesting, but very poorly defined, lets have a simple example.

Robert, correct me if I'm wrong, but the idea is basically as follows, as I understand it:

Here is a position. It's black's turn. The biggest move is a but black didn't see it.

Click Here To Show Diagram Code: [go]$$B black to play $$ +---------------+ $$ | . . X O . . X | $$ | a . X O O O X | $$ | . X X O . . X | $$ | . X O O O O X | $$ | X X O . . X X | $$ | O O O O X X . | $$ | . O . O X . X | $$ +---------------+[/go]

Here's perfect play

Click Here To Show Diagram Code: [go]$$B end score B+3 $$ +---------------+ $$ | . . X O . 3 X | $$ | 1 . X O O O X | $$ | . X X O . 2 X | $$ | . X O O O O X | $$ | X X O . 4 X X | $$ | O O O O X X . | $$ | . O . O X . X | $$ +---------------+[/go]

Here's actual play:

Click Here To Show Diagram Code: [go]$$B :w4: pass, end score B+4 $$ +---------------+ $$ | . . X O . 1 X | $$ | 5 . X O O O X | $$ | . X X O . 2 X | $$ | . X O O O O X | $$ | X X O . 3 X X | $$ | O O O O X X . | $$ | . O . O X . X | $$ +---------------+[/go]

Now, the analysis:

Move

is a mistake. Now perfect play is:

Click Here To Show Diagram Code: [go]$$B end score: W+1 $$ +---------------+ $$ | . 4 X O . 1 X | $$ | 2 . X O O O X | $$ | 3 X X O . 5 X | $$ | . X O O O O X | $$ | X X O . 6 X X | $$ | O O O O X X . | $$ | . O . O X . X | $$ +---------------+[/go]

So black's mistake costs 4 points.

White's move

also misses perfect play, and also loses 4 points, because black could revert to the original perfect play.

again loses 4 points, because white can revert back to the W+1 diagram.

pass loses 5 points (white can move from B+4 to W+1)

is perfect play.

So in the end, black lost 8 points in this end game, and white lost 9 points.

Correct?

HermanHiddema · Post by **HermanHiddema** » Thu Nov 27, 2014 8:16 am

RobertJasiek wrote:Uberdude, endgame is concerned with playing the bigger moves. Move 6 plays in the smaller gap and therefore is a smaller move than if played in the wider gap. Since the gaps are of simple nature (one stone at each end of the gap), such a simple consideration of width is valid and good enough to assess that the move is a mistake. Its exact loss value is a matter of further study.

Robert Jasiek is German, therefore: If you meet someone who is German, that person is Robert Jasiek.

This

is not endgame by any definition.

Bill Spight · Post by **Bill Spight** » Thu Nov 27, 2014 8:36 am

RobertJasiek wrote:Uberdude, endgame is concerned with playing the bigger moves.

Takagawa wrote: The endgame is fighting strength.

RobertJasiek · Post by **RobertJasiek** » Thu Nov 27, 2014 8:39 am

Herman, White 6 is not endgame, but endgame-like because it can be avoided and corrected by an endgame-like principle. Part of what made me stronger from 4d to 5d was a more liberal and tolerant view of what constitutes or can be played like endgame. Expert system computer go programmers have known that for at least 20 years. (It does not require a German to get this insight.)

Your example is correct (although I have not checked each value). Now, which conclusion do you want to draw for it being poorly defined?

Bill, if you are reading this, which insights did token go reveal?

EDIT: fighting strength and bigger moves are not mutually exclusive:) Also compare GoWorld 41.

Everybody, I forgot to ask: which GoWorld issues have Ishida's value estimates of beginner mistakes?

HermanHiddema · Post by **HermanHiddema** » Thu Nov 27, 2014 8:47 am

RobertJasiek wrote:Your example is correct (although I have not checked each value). Now, which conclusion do you want to draw for it being poorly defined?

Well, it really wasn't defined at all. I tried to sort of work backward from the posted game example.

You speak of rounding fractional values and mention miai values, but also equate one rank to 14 points, which is a deiri value. My example avoided the issue of sente/gote altogether because it was not clear to me how you handled it.

Bill Spight · Post by **Bill Spight** » Thu Nov 27, 2014 8:49 am

Click Here To Show Diagram Code: [go]$$B :w4: pass, end score B+4 $$ +---------------+ $$ | . . X O . 1 X | $$ | 5 . X O O O X | $$ | . X X O . 2 X | $$ | . X O O O O X | $$ | X X O . 3 X X | $$ | O O O O X X . | $$ | . O . O X . X | $$ +---------------+[/go]

Play...Gain.....Gain from correct play.....Loss

.....0.5..........2.5....................2.0

.....0............2.5....................2.5

.....2.5..........2.5....................0

Total loss by Black: 4.0

Total loss by White: 4.5

RobertJasiek · Post by **RobertJasiek** » Thu Nov 27, 2014 9:26 am

Herman, 14 points = 1 rank is a miai value.

Bill Spight · Post by **Bill Spight** » Thu Nov 27, 2014 9:27 am

Uberdude wrote:Here is some evidence your numbers are too high. I was a 2d and played the endgame of a game against a 4k. We swapped colours and did it again. The difference was about 15 points. Now of course there are problems from this like not playing optimally if you are behind or the 4k learning from my first game, but this suggests the point difference in endgame skill is about 3 points per rank, which is a lot less than 14. I would suggest more experiments of this nature to get a better idea of how the difference in endgame skill of different ranks relates to points.

Back in the 1970s a go magazine ran some articles with endgame tests. You could play out a position with an opponent and then compare your result with the pros. I was 3 dan and played against a shodan. I averaged 11 points better than the pro result. We did not switch sides, so maybe I would have gained 11 points that way, too, for a difference of 22 points.

Anyway, this suggests that of the 2 stone difference between us, around 28 points, 11 points was due to the endgame difference. That's a little high, but my endgame is pretty good.

What counts as endgame is not very well defined, but my guess is that around 1/9 of strength difference is attributable to the endgame, on average. That comes to 1-2 points per stone. That is consistent with your results.

Life In 19x19

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