Djinn

• Introduction
• Elo rating
• Overview
  
• Technical Details
• Download (New Version 0.925x)
  
• Computer Chess Reading List
• Acknowledgments
  

Introduction

Djinn is a computer chess program and an ongoing hobby (obsession!?).  It is the third complete chess program I have written.  The first was written in BASIC while I was still in High School and was weak beyond description.  It did play legal chess though, including en'passant captures and castling.  My second effort (also unpublished) was written about 12 years ago for Window's 3.1.  It included its own graphical user interface (GUI) and also was very weak (an ongoing theme of ALL my chess programs!!)  It did not have a quiescence search but instead used a static-exchange evaluator, combined with the evaluation function, to score the tree leaves.

Djinn is my first real attempt at making a strong engine.  It does not have its own GUI, but instead supports the Winboard protocol (specifically version 2).  I also believe the engine can be run under Arena (an excellent freeware chess interface for Windows ®).

Djinn is a modern chess program.  What this implies is that Djinn utilizes most of the algorithms found here.  Djinn is NOT a clone of any other engine (including Crafty, Robert Hyatt's open-source program).  I find the entire idea of copying, or even worse simply recompiling, someone else's program inexplicable and worse criminal.  What intellectual satisfaction can anyone get from stealing someone else's work? That said, I throughly enjoy discussing computer chess algorithms and techniques with anyone.  I'm also very open about the ideas I've incorporated into Djinn.  Lastly, I've tried to give credit to the original authors of all relevant ideas.

Elo Rating

Elo ratings are notorious things, but the question inevitably arises, just how strong is this thing and why should I care?  From my testing and results in various internet tournaments, I would rate the latest version of Djinn at roughly 1900 on an older Pentium and perhaps 2200-2300 on a fast Athlon or P4.  Djinn plays regularly on ICC, under the handle DjinnX. The program usually maintains a standard rating of 2250-2400 running on an AMD ® Athlon FX-51.  Of course, ICC ratings should be taken with a liberal grain of salt, since they are notoriously high.  Still unless you are an International Master or better, Djinn should occasionally whack you (as will most modern chess programs).

Acknowledgments

• Djordje Vidanovic for his interest in the engine and his willingness to help me with a new opening book (completely unsolicited)!

• Robert Hyatt for his willingness to answer just about any question, regardless of how trivial.  I also admire his obvious passion for the field.  Crafty is one of the strongest programs around and his knowledge of the field simply amazing.
  

• Eugene Nalimov for his endgame tablebases work and his generous gesture of allowing me to use it (for non-commercial usage of course).  I don't know how many points or half-points his work has enabled Djinn to save, but if nothing else my blood pressure goes down considerably when the engine hits a 4-5 man ending against a strong opponent.  If you ever decide that your head doesn't hurt enough, you should take a look at Eugene's code.  It will definitely make your brain ache (it's amazing stuff).

• Tord Romstad and Daniel Shawul for sharing their ideas on Late-Move Reductions (LMRs) with the chess programming community.  People like Tord and Daniel are the reason it's still fun to pursue this crazy hobby after all these years.
  

• I'd also like to thank Olivier Deville, Günther Simon, Leo Dijksman, Claude Dubois and Karl-Heinz Soentges for including Djinn in their various tournaments and for just being class acts in general.  In one way or another they have ALL made the experience of computer chess programming much more enjoyable. 
  

• To Jan, she knows why.