CCRL Discussion Board

Ok, KK, I see what you are saying ... now. But it's a subtle point and I misread what you were saying, and maybe others will too. So maybe my clarification is not wasted. As you say, if your WDLs are verified as correcthould be), you can use them as a launchpad to create whatever DTC or DTZ (but not...

While we are talking about boundaries ... Most people assume that the winner does the conversion into the next endgame. This is not always true: the loser can convert a Pawn, or be forced to capture. N Wirth, back in the 1990s, inherited a piece of code that assumed 'winner does all the conversions'...

I've used 'WDL' and 'WDL EGT' consistently in this forum so if you can text-search the whole thing on those tags, you'll find what I've previously written about the utility of WDL. I think the SHREDDER team have written about the utility of their SHREDDER bitbases elsewhere. While you can compute KP...

With WDL sub-endgame tables, however, any errors in DTx will remain there and not affect the other tables. This should allow to relax the verification requirements somewhat (e.g., to postpone the verification, because any error can be corrected locally without having to recompute a large number of ...

Plenty of sub-7-man statistics at http://ticc.uvt.nl/icga/games/chess/endgames.php Your chart is quite amusing but I'd be tempted to go to a log-scale on both axes. There are clever ways to index permutations to meet certain requirements - but these do not involve a 'move' relationship between the f...

A type B1-x zug is defined to be a position where the side to move. wins - but would win more quickly (in terms of the DTx metric) if it could 'pass' the move across to the side not to move. c.f. http://centaur.reading.ac.uk/23047/. The DTx zug-depth is the DTx-difference in depth between the positi...

Would certainlly be worth knowing if the Lokasoft URL is still live and usable ... anyone had any success with it?

g

This is a fascinating study but I wonder if Black's 16...Qxb6+ (hoping that White would get on the wrong foot with regard to the Trebuchet position) qualifies as 'best defence' as Study Protocol requires. DTM was -58 but after 17.Kxb6 was -15. Black surely could have made White work harder. Maybe th...

Took me a while to get enough 'space' to work through Arpad's explanation which is logical enough ... there were a number of positions with the wK on 'x' and the bK on 'y' and these were accounted for. Ok: I guess we're doing what the chess engines do. Once they see a position they've seen before in...

... as found at http://www.freesoft.org/software/hoffman/

Thanks in advance: g

Something simpler, even trivial:

8/8/8/pP6/4R3/3K4/8/1k6 w ... DTC = 2, DTM = 4, DTZ = 1

Minimising DTC, 1.Ra4 ... minimising DTM, 1.Kc3 ... minimising DTZ, 1.b6 (obviously not a time-wasting move )

Maybe this can be demonstrated with less men and/or less plies?

g

Agreed about 'key positions' in endgames. I'm open to suggestions, and I'm going through J.Nunn's first trilogy now - and maybe the 2nd trilogy which I also have has something to say.

My list at the moment is basically Philidor(1777) for KQKR and the 'Roycroft' Kc2Nb2 pseudo-fortress for KBBKN.

g

Arpad ... thank you for your explanation of the Hornecker study which I will ponder. The study is a neat example of something I'm writing about at the moment, so I may use it (and your info) with acknowledgement for your contribution. Basically, if one could calculate EGTs for variants of chess like...

Arpad Rusz’s contribution is excellent and timely. Siegfried Hornecker’s study is HH#75649 in Harold van der Heijden’s Study Database, http://www.hhdbiv.nl/ for those who want to explore. In discussing it, I will use the following notation: - - - - - °: stm has only one ‘physical’ move on the board ...

To kronsteen and others of course ... Thank you for your interest in the 'uniqueness' and 'looping' challenges. I think we are using different words but converging rapidly in terms of the ideas. In my 'Strategies for Constrained Optimisation', http://centaur.reading.ac.uk/4566/ , I defined subsets o...

Replying to kronsteen's last contribution ... 'DTC' is computed on the basis that the winner wants the shortest path to 'conversion' and the loser wants the longest path. So 'conversion' is a goal for both sides (and 'DTC' is an abbreviation for 'DTC-DTC' or 'DTCok/DTCnot-ok') .. but it is a goal th...

These are the figures I just retrieved from some work which I must have done years ago and forgotten about. They are based on my decanting of Nalimov's figures into spreadsheets, and then into a summary spreadsheet. Therefore they should be basically Nalimov's figures - which follow a nomenclature f...

The sub-7-man (s7m) EGTs, by my reckoning, contain values and depths for some 3,409,699,385,208 chess positions: that's 3.4*10^12 for short! These are the legal positions, counted in Nalimov terms, and do not include what he calls 'broken positions', e.g., with the sntm in check. Maybe others have s...

byakuugan's contribution prompts me to mention something similar that I've been thinking about for more years than I care to mention now. The sub-7-man (s7m) EGTs, by my reckoning, contain values and depths for some 3,409,699,385,208 chess positions: that's 3.4*10^12 for short! Not a set of informat...

Ok, thanks for the clarification that DTX means 'Depth to Capture and/or Mate' rather than just 'Depth to Capture'. When I first came up with the systematic DTM, DTC, DTZ in 'Strategies for Constrained Optimisation' ... see http://centaur.reading.ac.uk/view/creators/90000763.default.html and particu...

I wonder if anyone has coralled Nalimov's position-counts to total up the number of sub-7-man winning, drawing and losing positions.

If so, may I ask you to save me quite a bit of work. Thanks - G

Kirill, I'm puzzled. DTC = 'Depth to Conversion of Force and/or Mate' ... and 'conversion' can be by capture and/or conversion of a Pawn. So your DTX would seem to be >= DTC, with the disadvantage that it may be undefined when DTM is defined, e.g., in KQK, KRK or KPK. There is a neatness about the f...

To see to what extent higher-level statements can be made about 'groups of positions' in the endgame, see John Nunn's six (!) books on the endgame. There was the first trilogy on Pawnless, Rook- and Minor-Piece-endgames ... and he's followed that up with a second trilogy recently.

g

If WILHELM or another chess-engine is using EGTs, they are probably DTM EGTs which take no account of the 50-move rule.

g

I traced HC's publication of AUMSs to Computerschach und Spiele v2, no.iv-v (2003).

Would still like to contact HC if possible. g