CCRL Discussion Board

Why not just request the page through HTTP and parse it? And if your software makes so many requests that parsing speed becomes an issue, then I guess the database server owner won't be very happy with the load you generate, and the server side will become the limiting factor.

All 9-piece positions are solved, in DTM metric. The longest line is 59 moves. All solved positions can be queried in the web-interface.

Never heard of it before. Looks very interesting.

Another mate in 59, with more normal material this time: http://kirill-kryukov.com/chess/various/4x4-Chess-mate-in-59-2.png (white to move) 2NR/1Pp1/K2P/1qkN w - - 0 1 1.Ka3□ c2 2.Ndb2!! Qa1+ 3.Kb4□ Kb1 4.Rd3!! c1N 5.Kc3!! Na2+ 6.Kd4□ Kc2 7.b4Q♢ Nxb4 8.Rc3+!! Kb1□ 9.Rb3!! Na2 10.Na3+!! Kc1□ 11.d3!! ...

Mate in 59: http://kirill-kryukov.com/chess/various/4x4-Chess-mate-in-59.png (white to move) N1p1/1k1p/1B1B/BK1b w - - 0 1 1.Nc3!! Bc2+ 2.Kc1☉□ Kb4 3.Na2+!! Ka4 4.Nb4♢ Kb3 5.Bd4♢ Ka3 6.Bac3! Kb3 7.Bb2! Ka4 8.Na2! Kb3 9.Nc3☉! Kb4 10.Nb1+! Ka4 11.Na3!! Kb3 12.B4c3!! Ka2 13.Nxc4♢ Ba4 14.Na3♢ Bb3 15.Bb4...

Thanks for summing up the Nalimov's numbers. Indeed these numbers are/were available from the Nalimov's stat files, but are not terribly interesting for me because of the caveats you mentioned. If I ever compute tablebase for normal chess, my numbers will be impossible to compare with Nalimov's, bec...

Always interesting to discuss new metrics. I had also another metric idea that I call “distance to positive conversion” (DTPC or DTP maybe ?). DTC has the defect that it considers conversion moves by the losing side as goals. This results in the fact that these moves, which are generally threats (a...

Useful tablebases would be "Distance to Force" where the job of one player is to try to force a specific formation of pieces (maybe only 1 or 2 pieces are regarded in a formation), and the opposing player is not allowed to get checkmated either. It would be useful to examine such tablebas...

I myself am also guilty of sloppy counting, which I did for 3x3 chess: I never knew the number of unique legal positions until someone else computed it last month (54,826,983).

For a long time I've been curious to know the number of unique legal positions (NULP) in various 8x8 chess endgames. (See this 4x4 chess page for exact meaning I put into "legal" and "unique", although in 8x8 chess the casting and en-passant rights will have to be considered too)...

Took a look at the site but the download button doesn't yield anything. If it really generates 3-7 then this is amazing. Looking at the html didn't yield anything though in terms of a download, system requirements, etc. -Josh It seems you have to solve the CAPTCHA question at the top of the page fo...

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 ...

Making your own tablebase generator takes some time and efforts, but it's doable if you set out to do it. Even if you don't end up with something terribly efficient, you should be able to solve some simple endgames, like 3 or 4 pieces on any reasonable board size. Alternatively you may try to adopt ...

Spectrum of DTM values in 4x4 chess, for 3 to 8 pieces. Horizontal axis = DTM value, in order: draw, checkmate, win in 1, loss in 1, win in 2, loss in 2, etc. Vertical axis = Proportion of positions with this value among all positions with the same number of pieces, in percents (logarithmic). http:/...

Hi Marc, always nice to see you drop by. Since the board is so crowded in minichess even with a small number of pieces, and the pawns don't have far to go before conversion, one would expect DTC and DTZ to be close together and close to WDL in terms of compactness. Yes, as the board fills, DTC, DTZ ...

I decided to call this metric "DTX", because 'x' is used for capture in chess notation. So now the set of metrics I use will look like this (in order of decreasing table size): DTM, DTX, DTC, DTZ, WDL.

I am curious to explore "Distance to Capture" - another metric for endgame tables, inbetween the DTM (Distance to Mate) and DTC (Distance to Conversion). What would be a good abbreviation? "DTCa"? One of the reasons for my curiosity is that I discovered that DTC and DTZ are surpr...

Someone asked to see the 3x3 solver source code, so here it is. Note. It's written in 2003 as a toy, so I did not take is seriously at all at the time. There is no automatic verification, no proper interface, basically it's primitive in every possible way. For the same reason it's also a horrible so...

Current size of my tables (in bytes): Pieces NULP DTM Size DTC Size DTZ Size WDL Size 3 3,378 872 730 702 416 4 227,362 44,591 34,102 30,259 13,056 5 8,803,638 1,515,735 958,352 835,240 373,192 6 226,104,696 34,832,691 18,260,652 16,001,827 7,592,409 7 4,143,416,867 568,131,821 241,138,993 214,736,7...

Hi Derek, and welcome! I think it's an interesting and welcome initiative. - legality of using existing 'free' web services? Legality should be no issue, but the problem is that you won't find a free or cheap web-host that will allow you to host any TB-sized data. At least I could not, and I tried. ...

Let me guess, is it as available and as useful as their earlier efforts (which means unavailable and therefore useless)?

There are 3,677,542,994,054,890 unique legal positions in 4x4 chess. This time it's not an estimate, but the exact number. This is 21,981.3 times more than in 3x4 chess.

As expected, our tournament host is pulling ahead against all odds.

MaxDTM positions with 7 and 8 pieces:

7 pieces, 54 moves
8 pieces, 56 moves

Bugs reported by Codeman are now fixed too. Thanks a lot and please let me know if anything else is broken!