BOOKUP - EPD

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EPD files allow BOOKUP users to get analysis from the world's strongest playing programs. This page describes the steps needed for particular versions of MChess Pro, Rebel, Chess Genius, HIARCS and Zarkov.

EPD stands for "Extended Position Description" and is a standard for describing a set of positions in ASCII characters. If that sounds too complex, don't worry. You don't need to know any of the technical details to benefit from EPD files.

The idea is to create a collection of positions from BOOKUP in a format that an analyst program can understand (EPD). Then the analyst program reads these positions and adds a numeric assessment and a principle variation.

The numeric assessment is a number that describes the value of the position for White or Black. It is usually on a scale of 100 points for a pawn. For example, a numeric assessment of +50 means the analyst program believes the position is slightly better for White or the advantage is worth about half a pawn. A numeric assessment of -300 means that the analyst program believes Black is ahead by about a piece (or three pawns). The numeric assessments depend somewhat on the strength and style of the analyst program and the amount of time spent analyzing each position.

After analysis of the EPD file is complete, BOOKUP imports the file. You can optionally protect any existing analysis by having the new analysis added to the old principle variation or you can have older analysis completely replaced by the newer information.

Note: The built-in Zarkov engine does not require this step. The information is imported during the analysis. In fact, you will get a warning message if you attempt to import the EPD file into BOOKUP.

The analysis then appears with each position in BOOKUP as a numeric assessment (near the Informant rate symbol) and as a "principle variation" in the comments.

The BOOKUP for Windows User's Guide describes the EPD export controls on page 35 along with an example of the process on page 36.

How to Use EPD Files

The first step is always to create the EPD file with BOOKUP. Even when using a built-in engine like Zarkov 4.0, you must first put the positions that you want to analyze into an EPD file.

There are brief notes about each analyst program with EPD capability:

MChess Pro 5

Chess Genius 3

Rebel 8

Zarkov 2.6 and 3.0

Zarkov 4

HIARCS 2.1

Importing the EPD File

After the analyst program has processed the EPD file, you must import the resulting analysis back into your book-on-disk. In BOOKUP for Windows select Import Positions... from the EPD menu.

You must import the EPD file into the same book-on-disk used to create the EPD file. Otherwise positions in the EPD file may not match those in the book-on-disk.

MChess Pro 5

MChess Pro version 5 was the 1995 Absolute World Microcomputer Chess Champion and one of the latest playing programs to add the ability to analyze EPD files from BOOKUP. The steps aren't as intuitive as they could be, however. When creating the EPD file in BOOKUP be sure to remember the drive, directory and name of the file.

In MChess Pro 5, select the playing strength for the analysis. (The default setting is 3 minutes per move.) From the File menu select Position Archive and choose Select Archive. Use the mouse or arrow keys to select the EPD file for analysis. Here is where you'll need to know the drive, directory and file name of the EPD file. Once the file is selected, it will have a '+' next to the file name. Then press the Esc key or the right mouse button.

Again from the File menu select Position Archive and choose Analyse Archive. MChess will stop after the analysis is complete.

An early version of MChess Pro 5 had a bug which caused it to 'resign' lost positions during EPD analysis. Be aware that if you are hoping to have MChess Pro 5 analyze overnight you might return to find it with a resignation message. Press a key and the process will resume.

Once MChess is finished analyzing the file import the EPD file back into BOOKUP.

MChess Pro 5 may also stop analyzing an EPD file which contains a checkmate. The only work-around at this point is to open the EPD file with a text editor and delete the position that was being analyzed. Positions are analyzed sequentially in an EPD file. Delete the first line (or "record") which does not contain analysis at the end of the line. Then have MChess Pro 5 analyze the file again. It should skip over the positions already analyzed.

The new MChess Pro 6 has not yet been tested. The programmer, Marty Hirsch, believes the resignation bug has been fixed.

Chess Genius 3

To analyze an EPD file with Chess Genius 3, select a playing level. Then from the Opponents menu choose Process EPD... Chess Genius will allow you to switch to any drive or directory and open any file ending in .EPD.

Once Chess Genius is finished analyzing the file import the EPD file back into BOOKUP.

Chess Genius 3 may also stop analyzing an EPD file which contains a checkmate. The only work-around at this point is to open the EPD file with a text editor and delete the position that was being analyzed. Positions are analyzed sequentially in an EPD file. Delete the first line (or "record") which does not contain analysis at the end of the line. Then have Chess Genius 3 analyze the file again. It should skip over the positions that already have analysis.

Zarkov 2.6 and 3.0

Zarkov versions 2.6 and 3.0 for DOS have no menu options for analyzing EPD files. Instead, command line parameters must be used. Here is an example startup command for Zarkov taken from page 36 of the BOOKUP for Windows Users's Guide. Zarkov is being told to analyze the position.epd file in the c:\bookup directory and spend five minutes (300 seconds) of time (-t) on each position:

zarkov -s c:\bookup\position -t 300

Once Zarkov 2.6 or 3.0 is finished analyzing the file import the EPD file back into BOOKUP.

Zarkov 4.0

Zarkov version 4.0 currently exists only as a built-in engine for BOOKUP 1.5 for Windows. There is no need to import EPD analysis after using Zarkov 4.0 because the information is imported directly into each position during the analysis.

When BOOKUP uses Zarkov 4.0 for EPD anlysis, the EPD file is not updated with the analysis. This is handy if you want to analyze the file again with different settings. If you try to import any EPD file without analysis you will get a warning message from BOOKUP.

HIARCS 2.1

This particular version (2.1) of HIARCS generates EPD analysis with the numeric assessment signs switched when Black is to move. This was the fault of BOOKUP, not of the HIARCS programmers! To get correct analysis a checkbox must be set when importing an EPD file back into BOOKUP only if the file was analyzed by HIARCS 2.1. When importing EPD analysis from other versions of HIARCS (and all other known analyst programs) this box must not be checked.

Rebel 8

Rebel 8.0 is the newest program to add EPD capability. To analyze an EPD file in Rebel 8 set the desired playing level and choose Analyse Bookup EPD-File from the PGN menu.

Once Rebel 8.0 is finished analyzing the file import the EPD file back into BOOKUP.

Get more information on Rebel programs.