About Private Chess engines

by Aaron Tay (email)

Private Chess engines are a interesting breed. These are the Chess engines which authors (for various reasons) have not yet or do not intend to release either for free or as a commercial engine.As such these are Chess engines that money literally cannot buy.

These private Chess engines range a lot in strenghts. Some like Ferret,Insomanic are commercial level, while others like Zarkov,Diep were commercial Xboard versions.

Many more though are new Chess engines taking their first steps and are weak and buggy.

It would be a impossible undertaking to list all known privateware (even if we restrict them to Xboard/Winboard engines). According to some estimates, there are over 200-300 Xboard/Winboard engines alone.

The following list are some of the more interesting,mature and well established Chess engines that I hope will be some day released (either as freeware or commercially). Some of those in the list (I won't name Names) in fact have being promised by their authors to be released "some day". Others of course, will probably follow in the footsteps of Ferret (the pioneer and ultimate privateware except Deep Blue :) ) and remain privateware until maybe a company with a big enough wallet tempts them to release them as a commercial engine.

I actually added the email addresses of the authors of the chess engine on this list but removed them because I had visions of people using my website as a quick launch pad to fire off emails begging for private copies. Needless to say this can prove annoying. If you really want to contact the authors on this list, you can look around at Computer Chess Club or log on to ICC.


31-08-2002 Since the beginning of this list, 2 private-ware engines (Aristarch and Ameteur) were released as freeware and hence are taken off the list. Added Ruffian to the the privateware list. There are some signs that Ruffian and Post-Modernist and maybe even Zarkov?? might be released as well.

07-10-2002. Ruffian released as freeware , so removed off privateware list.I appears to have neglected several strong French programs. While Anmon,Dragon, Pharaon (formerly Zchess), The Crazy Bishop are famous freeware staples, there are several strong french privateware programs that have being around almost as long.
Chess Wizard by Frederic Louget is a Twice French Computer Chess Champion (including 2002). It usually places within the top few engines in the French Championships (assuming it doesn't win it!) . This is a feat because the strong competition from commercial Tiger and other strong freeware and privateware French engines (Anmon,Pharaon are strong ranked ametuers) means that the French Computer Chess championships are one of the strongest in the world.

21-03-2003 Deep 9 was a new program that many people were looking forward to. Personally I had my doubts so it was never added to my list. It turns out I was right it was just a clone of the free source Pepito. Isichess added to list.

28-05-2003 Dorky released and is removed from list.

23-06-2003 Alarm added to list. Released and removed Jul 2003

25-06-2003 Cyberpagno was removed, after Gunter Simon pointed out to me that it was released already. Thanks! Postmodernist will be released soon. It's nice to see some of the long time privateware engines being released.

24-07-2003 Postmodernist released. Yet another "oldie" released! Will we get Monsoon, Hossa, Zarkov next?

26-10-2003  Ikarus by Munjong Kolss added to list.

26-10-2004 Zappa released. Nexus appears also to be very strong now.

Engine ICC Handle Author ICC Best
Chess Wizard Chess Wizard Frederic Louguet -/3055/- NA
Chester Chesterx Steve Timson 2838/2974/2663 NA
Diep Diep Vincent Diepveen 3043/3098/2640 Diep was commercial.
Falcon Falcon Omid David Tabibi NA The much weaker Genesis by the same author is available.
Ferret Ferret Bruce Moreland 3155/3343/2825 Gerbil by the same author is available.
Grok Grok Peter Kappler 2538/2668/2346 NA
Hossa Hossa Jakob Hossa 2915/2794/2512 NA
Munjong Kolss
Was released as Chessbase YT
Insomniac Jzinsomaniac James Robertson 2767/2925/2711 Formerly known as JRCP
Isichess Isichess Gerd Isenberg unknown ICC account is dead
Maxima QueenMaxima Hof&Hajeweit 3073/2735/2449 NA
Messchess messchess Mridul Muralidharan 2487/2592/2399 NA
Monsoon (down) Monsoon Scott Gasch 2677/2942/2631 Despite the existence of a manual, it's not released yet.
Nut Formerly MissSilicon Andrew Dados NA Account at ICC seems to be dead
Rookie Blik Marcel van Kervinck -/2582/2649 NA
Searcher Searcherx Frank Philips 2618/2959/2621 NA
SpiderChess NA Martin Giepmans Unknown NA
Tinker Tinker Brian Roberson 2617/2660/2480 NA
Zarkov 4.5X ZarkovX John Stanback 3031/2990/2646 Old versions were commerical

This list was compiled from the engines taking part in CCT and Will Singleton's (now defunct) Green list.


All ratings recorded are "best" rating, this gives only a rough idea of the strength of some engines. Still to achieve a best rating in blitz of 2800-3000+ is a feat only strong mature engines can meet.And to achieve a best of 2600+ would put you within the range of some of the best ametuers.

Almost all these engines above are on par with some of the best current freeware others are weaker to a certain degree and some are better. For reference, Yace (c) [A leading freeware engine] running on an average hardware of 1.2 Athlon today has a best rating of 2823/3083/2725 [Lightning/Blit/Standard]