The four CDs in the "Chessbase Endgame Turbo" contain the tablebase files that can be used by many chess playing and analysis programs. So what the heck is a tablebase? A tablebase is a database of endgame positions that is accessible by a number of chess engines, these include Fritz 6, Junior 6, Nimzo 7.32 and Hiarcs 7.32. In fact any program that can utilize tablebases in the Nalimov format can use the tablebase information provided on the CDs (this includes Crafty and some other winboard compatible engines). So the endgame turbo CDs may be useful in other non-chessbase programs as well.
Tablebases allow a chess engine to play nearly perfectly in the endgame phase. I say "nearly perfectly" because there are a few isolated cases where the tablebase files may not indicate the quickest win. However, the tablebases will never allow an engine to throw away the win or draw. Programs that are set up to use the tablebases properly can "probe" the tablebase information when the engine is examining candidate moves in it's search. For example, this information can be used by the chess engine to make a transition into a theoretically won endgame.
The Endgame Turbo contains tablebases in the Nalimov compressed format. This is a different format than that used on the Ken Thompson endgame CDs, and the two are not compatible. There are also a number of other differences as well. The most significant of these is that the Nalimov format can account for en-passant captures, whereas the Ken Thompson tablebases can not. Thus there are no P vs P endgames on the Ken Thompson CDs.
You should know that the endgame tablebases can also be downloaded off the internet. But this is only feasible if you have a very fast net connection to use, and transmission errors can creep into the files. That's why most people chose to simply purchase the CDs.
This four CD set actually contains both a program for building/creating the tablebase files, and the actual tablebase files themselves. The CDs also include a Chessbase analysis/playing engine for directly accessing the tablebase information (this means that if you do not have Fritz 6, Hiarcs 7.32 or Junior 6, you can still access the tablebase information from Chessbase or Fritz). Tablebases covering endgames with five or fewer pieces are covered in this collection. While the collection of tablebase files included on the CD are not complete, they cover most of the endgames that will be commonly encountered (for instance, there is no tablebase file for 3 white queens + black king + white king).
You can choose to either use the building program, or simply copy the files. The latter is the fastest option. However, using the tablebase building program, you can build all the tablebases, including those that might not be on the CDs. If you do decide to use the tablebase generator program on the CD, then you need to have enough memory and CPU horsepower to build the necessary files in a reasonable amount of time. If interrupted, the generator program can pick up where it left off.
Owners of Hiarcs 7.32, Junior 6 and Fritz 6 should note that the tablebase building program is already included on the program CD, so technically, you already have the tools to build the tablebases if you own one of those programs. But you will need to dedicate the time and resources to building the files yourself; whereas the Endgame turbo CD's allow you to copy all the important files to your hard drive.
I would also like to thank Anders Thulin for his very informative USENET posts on the topic of tablebases.
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