Is anyone familiar with the .wdl and .dtz formats for the 6 man tablebase that are available?

I already confirmed that both aren't needed, however they both store different information. Goal is to determine which one would fit what I want to do.

-I know there are other forums out there for this. I'm a new member on one of them but trying to see if anyone here is familiar with this is all.


4 Answers 4

  • WDL gives win/draw/loss for a position
  • DTZ gives distance to zero for the 50-moves draw rule

Both files are needed, absolutely. Chess engines assume both files are there, and would only check one of those at run time. It's your responsibility to make sure you have both files. There's a good opportunity your engine will crash if you don't.

You're giving yourself trouble if you leave out one. Download them both or do nothing.

  • Thanks SmallChess. Wandering why I was told that I didn't need both.
    – hangejj
    Feb 12, 2018 at 2:14
  • Also, since I run the 3-4-5 already, can I just add all of the 6 man files to the 3-4-5 location? I also read that the 6 man looks for the 3-4-5. Hoping that simply adding the 6 man files to the same location folder is all that is needed for the engine to recognize the tablebase.
    – hangejj
    Feb 12, 2018 at 2:26
  • @Schmoe that will work
    – SmallChess
    Feb 12, 2018 at 6:05
  • 1
    Neither Stockfish nor Cfish crash in this case. They make use of whichever tables are available. However having WDL is a prerequisite for using DTZ.
    – Niklas
    Aug 11, 2018 at 22:31
  • WDL without DTZ can be very useful you should edit the answer to include this. Jun 28, 2019 at 5:29

So called "DTZ" syzygy tables are a supplement to WDL ones; without WDL, they're mostly useless.

Stockfish/Cfish will work with WDL only, but then it might be unable to win a difficult won (as per tables) position. "Outside" the tables, that is, as long as you only analyze positions with more pieces than your tables have, "DTZ" syzygy tables are not required.


Stockfish and LCZero can work with WDL without DTZ, but it might not find the optimal way to win under engine playing conditions. If you are only interested in analyzing positions with tablebases, you don't need the DTZ to tell you if a position is won or loss (since WDL already does that), but having DTZ will guarantee the winning/bestplay sequence if the engine cannot figure it out from probing WDL alone.


You should use both if you have the space. From syzygy-tables.info:

Most of the time (during search) only WDL tables are used. Keep these on SSD storage if you can. DTZ tables are generally only used to finish the final phase of the game ("at the root").

More info at https://www.chessprogramming.org/Syzygy_Bases

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