Wisdom is knowing how

   little we know -- Socrates

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Started in 1980, retired in 2004 REBEL was baptized into ProDeo, latin for gratis according to Dutch tradition.

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Dear chess programmer,

We like to introduce a programmer code, a pledge to be transparent about the origin of your chess engine and ask you to subscribe via this form in case you agree.

We will maintain a list on this page of chess programmers who subscribed to the code.

Your email address will be held strictly confidential and only used for verification purposes in case there is doubt on your identity.

Thanks so much for your support of this initiative.

Ed Schröder
June 13, 2012



I hereby declare that the origin of my program:

is an original work.
is derived from ..... (fill in below).
is derived from ..... but original at code level in the meantime.
is inspired by ..... but absolutely original at code level.

I further declare:

1. Not to copy the work of other programmers without their express permission.

2. Not to reverse engineer the work of other programmers without their express permission.

3. When I use an idea from other people I will mention the source in the README file unless they are widely recognized, standard, and present in the chess programming Wiki. The latter to avoid listing zobrist, alpha beta etc.

Your name        

Your program     

Your email        




 List of programmers who subscribed to the code


     Name  Program(s)  Status  Your comments
 1   Ed Schröder  Rebel | ProDeo  Original  
 2   Julien Marcel  Predateur  Original

 Numerous ideas taken from books, CCC 

 forum, Bruce Moreland's website and CPW


 3  Reinhard Scharnagl
 SMIRF  Original

 Some ideas might be inspired be reading

 chess and AI literature.

 4  Lucas Braesch  DiscoCheck  Inspired

 Inspirations from: Fruit, Stockfish, Umko.

 Details in source code comments.

 5  Heiner Marxen  Chest  Original

 I did not record where I picked up ideas.

 I never picked up (copied) any code.

 6  Roberto Munter  Vitruvius  Derivative

 Derived from Ippolit series, but in the meantime

 I have changed many parts and added other code

 and original ideas.

 7  Miguel A. Ballicora  Gaviota  Original

 8  Dan Honeycutt  Bruja | Cupcake  Original

 I document where stuff came from in the 

 program comments rather than the readme. 

 I have most of them but I won't swear that I

 have them all. Bruja is source on request

 and Cupcake is open source so anyone

 interested in originality can check for 


 9  Charles Roberson





 The inspiration comes from several books.

 AI books: Artificial Intelligence by Patrick Henry

 Winston; The Handbook of Artificial Intelligence

 by Barr, Figenbaum & Cohen; The Art of Computer

 Programming by Knuth; various ICGA publications,

 and more.

 Numerous conversations with others in the field

 including Bob Hyatt, Brian Richardson, James Swafford,

 Vincent Diepeveen, Gian-Carlo Pascutto, Shay Bushinsky,

 Amir Ban, GM Boris Alterman, Andrew Williams, James

 Robertson, Rudolf Huber, Stefan Meyer-Kahlen, GM

 Sergey Kudrin and many more.


 Marcel van Kervinck




 I find it difficult to extract concepts from just

 looking at code, which is why I hardly ever do

 that. In the meantime, I see nothing wrong with

 allowing others to reuse open source game

 playing code in tournaments as long as

 1. sufficient differentiation is demonstrated, and

 2. equal attribution is given to the original authors

 (even if modified). Additional permission would not

 be needed in case of GPL or BSD-style license.

 If such a program wins, then the prize and

 recognition should be shared with all contributors.


 Gerd Isenberg





 Dan Homan  EXchess  Original

 Source code provided with my program under

 GPL. Many ideas from many places as described in

 readme.txt and in the individual source code files. 

 Many ideas come from the old rgcc, ccc, chess

 programming wiki, etc discussions.... some of

 these (usually specific ideas) are documented

 in the code, for others (usually common things,

 I think) the specific origin of the idea to me is

 lost in time (development on-and-off over 15



 Nicu Ionita  Abulafia  Original

 The search is initial inspired from some ideas

 from Stockfish. Many ideas from CCC forum and

 Chessprogramming Wiki. At code level absolutely

 new as it's written in Haskell.


 Álvaro Begué  Ruy-López  Original

 Several ideas collected from the ICGA journal,

 and a couple from conversations with other

 programmers at WCCC events.


 Yves Lejeail  Milady  Original

 My engine is in VB.net.I started from scratch.

 Most of  the algorithms were from Bruce Moreland

 (alpha beta, quiescence,...). It take me years to

 tune the search in order to have a not too weak

 engine, although it is not very strong. LMR and

 NullMove seems to work, as well as extensions in

 case of checks in the main search, and checks in

 the first plies of quiescence. I have not TT, but 

 some kinds of History Tables which are depth

 dependent. I tend to try original ideas but they 

 usually don't work. I do not record very well the 

 improvements between versions.


 Richard Pijl  The Baron  Original


 Matthew Brades  FruitFly  Derivative

 Derived from Fruit 2.1 - but I think this is public



 Thomas Petzke  iCE  Original

 Written 100% from scratch, not using any public

 available code. Gaviota EG probing code was

 included temporarily to verify the internal node



 Steve Maughan  Monarch  Original

 Monarch is 100% original at the code level.  It really

 doesn't have anything special in it.  It's just a basic

 vanilla Alpha Beta with all the normal trimmings

 (killers, null move etc).


 Aart Bik  BikJump  Original

 Many ideas obviously inspired by the chess literature,

 but all code is original (except Nalimov probing code

 which is used with permission of Eugene Nalimov

 and Andrew Kadatch).


 Vlad Stamate  Plisk  Original

 My inspiration and knowledge came from Talkchess

 discussions as well as ChessWiki and open source

 chess programs: crafty, stockfish, gnuchess, etc.

 I document all the sources of inspiration (no copied

 code) in the readme accompanying my engine.


 Ben-Hur Carlos  RedQueen   Original

 Many ideas taken from Stockfish, Sloopy, Robbo

 and Gull. The code is completely written by myself

 with the exception of MT (random number generator),

 Magic Move Generator (By Praddu), some optimized

 bitCount and bitScan code snipets.


 Sune Fischer  Frenzee  Inspired

 Frenzee is a rotated bitboard engine. Every single line

 of code is handwritten by me there is no copy/paste

 from any other source. I feel it is my design, my ideas,

 my engine. However, I have over the years looked at

 other programs, like Crafty, Beowulf, Phalanx and other

 such oldies.


 If one were to look at the engine with the same scrutiny

 as was the case for Rybka then similarities would no

 doubt be detected. The move generator has something

 in common with Crafty, since it is a rotated incremental

 bitboard engine.


 Many of the eval terms are also public knowledge. I

 estimate that the original ideas in Frenzee probably

 amount to 100-200 points. The rest of its strength

 comes from implementing and tuning publicly known

 ideas or variations thereof such as PVS, nullmove,

 LMR, check extension, hashing and so forth.


 Richard Allbert  Jabba13032012  Original

 Jabba is written in C# - I've used many ideas from

 many other OS programs, as well as the CPW and

 the Talkchess forum extensively. I use them in the

 same way I use for example


 Heaviest influence came from Bruce Moreland's

 programming pages, and the comments in the crafty

 code documentation.

 My motivation is not engine strength - I derive most

 pleasure in writing engines from scratch that play a

 legal game with a few evaluation terms. See recent

 talkchess posts about C# performance!


 Having a 2200 engine on FICS playing 1000's of games

 is rewarding. My other reason is meeting people involved

 - such as at the CPT tournament hosted

 by Richard Pijl, or vis the online tournaments.

 On my home computer I have many self-written engines

 in pure C, C++, Java, C# and VB. This is why I release

 with source. Since I began in 2004, I've written many

 engine incarnations using Rotated BB, 0x88, Mailbox,

 Magic BB.


 Will Singleton  Amateur  Original


 Engin Üstün  Tornado  Original

 its original from starting on, first using rotated

 bitboards, and later changed that with pradu's Magic

 Bitboards. Of course some ideas are inspired and took

 from other open sources too. own hard worked over

 many years ago, never copied any lines from other.

 but only the code of nalimov for tablebase access is

 included to the source with permission.


 Jonatan Pettersson  Mediocre  Original

 Written from scratch and has open source. A few

 instances of code inspired from other people's work

 (in particular SEE logic), but in those cases has

 mentions of the originators.


 Bálint Pfliegel




 Portfish is the .Net port of Stockfish, so it is means to be

 an exact replica of Stockfish on the source level. Technically

 it employs solutions which are more natural or has to be

 formulated differently under .Net (object broker concept).


 WhiskySoda is my original engine, it is heavily inspired by 

 Stockfish/Portfish and GarboChess. Bitboard operations,

 FEN parsing, randoms, polyglot book handling are taken

 over from Portfish, search inspired by Garbo. It currently

 has a very basic eval, I will definitely use a lot of

 inspirations there from literature and other engines if

 there will be time to continue.


 Steve Webber





 Matthias Gemuh




 I looked at source code TSCP, ExChess, and Crafty

 before starting from scratch. Only other code seen

 again since then are code snippets in fora.


 Steve Maughan



 My new engine based on magic bitboards and a novel
 move dictionary approach. It's 100% unique.


 Thomas Mayer



 Most ideas inside, if not my own, were taken out of books,

 inspired by discussions on several forums or the result of

 conversations via eMail or directly at several computer

 chess tournaments. There never was any code copying,

 except the Nalimov access code and the code that is

 responsible to capture commands while thinking (taken

 from ExChess, Dan might remember the conversation

 long ago - afaik he has taken that from Bob who got this

 from Tim Mann, at least that is the info I have in mind)


 Luca Lissandrello



 The book was created by Colin Frayn (Beowulf), I have

 just modified and extended. I had his permission.


 Edsel Apostol

 Sam Hamilton



 Hannibal is original at the source code level. Many of the

 ideas are adapted from various open source engines and

 the knowledge repositories like chess programming wiki,

 and forums like CCC, and the Winboard forum. The only

 non-original code in Hannibal is the set of hash keys

 necessary for Polyglot book support.


 Emilio Díaz




 Secondchess is derived from Pam Nguyen's firstchess.

 Its goal is to add a couple of features missing in

 firstchess (castle, ep) and some simple enhance in

 evaluation and search, and keep the original idea of

 firstchess of being a pedagogical tool for beginners.


 Stan Arts


 Stan's Chess


 My venture into chessprogramming started around the

 year 2000 and has very much been from the ground

 up/never left it. Starting with a 1, 2.. 3 and eventually 4 ply

 nested loops pseudo legal mover. ..If you put it in check, it

 might put you in check..too! And trade kings.


 To Stan's chess. A buggy but working alpha/beta(ish)

 program. To Neurosis. A slow but semi serious effort with

 which atleast some points were won at the lower ends of

 the rankings at OTB tournaments halfway the 2000-2010

 decade. Entirely weak, strange and original but..don't tell

 any of the strong proggie people..way more fun.


 Andrés Manzanares



 Initially inspired by TSCP, but eventually completely

 rewritten implementing my own design and ideas. Many

 ideas taken from Talkchess, Chesswiki and various

 open-source engines.


 Michael Sherwin



 First taught myself to program in 80386 assembler and

 wrote a completely table driven PERFT called Godzilla.

 Then made a chess program in C called Carnivor, while

 teaching myself to program in C. Then decided to go

 BITBOARD and wrote RomiChess completely from my

 own head except for a couple of utility routines I got

 from Crafty and basic Alpha-Beta from books. I believe

 that it was Charles Roberson that said, RomiChess was

 the most original chess program that he had seen in

 a very long time.


 Joost Buijs



 The first version of Nightmare was written in assembler

 for the 8080 processor during the fall of 1977 and the

 spring of 1978. It was mainly inspired by the book

 'Chess Skill in Man and Machine' by P.W. Frey and by the

 book 'The Heuristic Programming Approach' by J.R. Slagle.


 The current v7.8x is a modern bitboard oriented engine,

 it is entirely written from scratch although the

 magic code is derived from Pradu Kannan's work and

 the Nalimov tablebasecode is used with permission

 from Eugene Nalimov and Andrew Kadatch.


 Nightmare is Windows only, it has an incomplete UCI

 implementation with most things hard coded, this is

 the main reason why I never cared to release it. I hope

 to address this weakness in the upcoming version 8.0

 which is partly finished.


 Pawel Koziol



 Rodent is a GPL program, started from codebase of

 Sungorus by Pablo Vazquez. It uses ideas from

 Fruit (eval, via Toga Log User Manual), Stockfish

 (some search parameters, most notably LMR reduction

 size) DiscoCheck, (hanging pieces eval), Crafty

 (material imbalance table) and a couple of others,

 mentioned in comments.


 What I consider original is some work on evaluation

 function (pawn chains etc.), but it has been inspired

 by CCC posts of Lyudmil Tsvetkov and Carl Langan.


 My goal is *not* to create an original engine to enter

 competitions, but to give end users the opportunity

 to change engine's playing style and strength.


 Steven Edwards



 My C++ program Symbolic is entirely original other than

 parts derived from my earlier original programs. While

 the Symbolic source is private, I have released

 sections of it for others to use. I also have released

 the full source of my ANSI C tablebase generator, my ANSI

 C SANKit, my Pascal program CookieCat, my C++ Audrino

 program Myopic and my Common Lisp CIL Chess In Lisp

 program. These are all original works with no source

 copied from any other author.


 I give credit for some ideas to Slate and Atkin for their

 on their Chess 4.x program and to Wilkins for his

 Paradise program.


 Stefano Gemma



 I've other chess engine: Drago, Raffaela and

 Freccia, all original works.


 Fabio Gobbato



 Many ideas find in chessprogramming and forums.


 Roland Stuckardt











Copyright ® 2012-2015  Ed Schröder