Prophet is a chess playing program that I’ve worked on in fits and starts since 2000. It’s a console based program, or “engine.” To play it yourself you’d have to first install Winboard or some other Winboard compatible user interface.


The latest version of Prophet3:

You can also download the source code from a Github repo:

Prophet is distributed under the MIT license.


The first version of Prophet was written around the year 2000 while I was an undergraduate. It was a conventional chess engine, utilizing a depth first alpha-beta search with iterative deepening and some conservative pruning to avoid searching stupid lines. I used this version to do some not-so-successful experimentation with TDLeaf (a form of temporal difference learning) and wrote about it in this abstract.

The second version was released in early 2007. I was in graduate school at that time and was using Prophet as a test bed for various parallel search algorithms. I continued to work on this version until shortly after finishing graduate school in 2008. If you’re interested you can read about it in this paper.

After that, Prophet lie dormant for a few years until 2011 when I started a second complete rewrite. By this point I had learned the importance of test driven design and wanted to apply that to Prophet. This is the codebase that I work on now. It still hasn’t achieved functional parity with Prophet2 but is already over 100 elo stronger.

How Strong is it?

Prophet is not currently tested on any ratings lists than I’m aware of, but I regularly test it against a suite of opponents at 3 minutes per game with 0.5 second increments per move. My testing shows Prophet3 to be very close in strength to Horizon 4.4 and TCB 0052. You can see a computer chess rating list such as CCRL to figure out how strong that is.

Prophet also regularly plays online at the Internet Chess Club, but those ratings tend to vary wildly. Normally the blitz ratings are in the 2100-2300 range.


Prophet has participated in some computer chess tournaments:

  • July 2017: Prophet3 20170319 played in Sergio Martinez’s Swiss Edition Group D, finishing 18/80 with 7/12 points.
  • Feb. 17-18, 2007: Prophet 2.0 participated in CCT9, finishing 33/52 with 3/7 points.
  • Oct. 28-29, 2006: Prophet 2.0 participated in the First Annual ACCA Americas’ Computer Chess Championships, finishing 7/16 with 3/5 points.
  • Aug. 12-13, 2006: Prophet 2.0 participated in the First Annual ACCA Presidents Tournament, finishing 16/18 with 2/6 points.
  • Feb. 25-26, 2006: Prophet 1.0 participated in CCT8, finishing 31/38 with 3.5/9 points.
  • Feb. 12-13, 2005: Prophet 0.something participated in CCT7, finishing 40/44 with 1.5/8 points.