September 2018

New and strong Polyglot book


Since 2016 it's a well established fact the polyglot Cerebellum opening book by Thomas Zipproth is the strongest available. Bookfish is able to beat the Cerebellum book. A 1000 game match ended in favor for Bookfish with a 536-464 (53.6%) aprox 25 elo stronger.


Why the name Bookfish and how it is done (it's a trick that need further refinement) see elsewhere. Also it's not clear how the book will score against other books. In the meantime download and enjoy the new book.





Update Noomen book

September 2016


Jeroen has opened his own blog. From now on you can download his latest artwork here.






Noomen book

August 2016


Here is a brand new update of my latest book, Noomen.ctg, with many corrections, additions, improvements, novelties and a few extra lines.


Please make sure always to use the following options, see Book Options (below picture how to).


  1. Tournament Book should be switched ON
  2. Minimum games should be set to 3
  3. Up to move should be set to 100


Not using these settings might result in a lot of weak(er) moves being played.


As usual, a big "thank you" to all the people who helped me to produce this new version. Enjoy!


Jeroen Noomen







New Noomen book

May 2016


After 6 years a brand new, varied and super strong CTG opening book by the hand of Jeroen Noomen, the Dutch specialist who in the past also was the author of the books for: Mephisto Polgar, Mephisto Milano, Openings module HG550 for Mephisto MM V, Mephisto Vancouver, Rebel / Pro Deo, Chess Tiger and Rybka.


The new book contains the latest developments in opening theory and is further enriched and checked with computer analysis. In my testing it showed a remarkable increase of playing strenght in comparison to Jeroen's last art work of 2009, the Rybka 3 opening book. How much? Find out yourself.



Documentation how to optimal use the book.





Jeroen Noomen collected works.


. Gambit Package

. ShortLines

. General

. GambitLines

Content Gambit Package



1. Noomen Gambit Lines 2015.pgn: a large testsuite for engine-engine testing, with gambits only.


2. Noomen Sharp Gambits 2015.pgn: a small testsuites (30 positions) containing the sharpest and most interesting gambits from Noomen Gambit Lines.


3. GambitLines.abk: the Noomen Gambit Lines pgn-file imported into an Arena abk-book, also meant for engine-engine testing. NOTE: if you are going to use this book in Arena, make sure that both

engines use this gambit book! It is not useful to test this book against other books, as it contains only the 247 gambit lines from the Noomen Gambit Lines pgn.

Approx. 37 Mb

Dear chessfriends,


Here is my little X-Mas surprise. I have made a few new testsuites, based on Worldchampionship matches. Below you can download the following testsuites, and one Arena book:




* Botvinnik_Smyslov_1957.pgn

* Botvinnik_Tal_1960.pgn

* Spasski_Fischer_1972.pgn

* Kasparov_Karpov_1985.pgn

* Kasparov_Karpov_1986.pgn

* Kasparov_Karpov_1990.pgn

* WorldchampionshipMatches.pgn (i.e. the above 6 matches in one PGN)


Arena book:


* WorldchampionshipMatches.abk (i.e. the above PGN translated into an Arena book)


Enjoy testing!

Jeroen Noomen

December 19 2015

23 Kb




Polyglot opening books


The polyglot book format is the most wide spread format in use by chess engines.



We converted the ancient (2000/1) REBEL (ProDeo) book to polyglot format. While old it is still a Noomen book and thus good.


A 200 game match confirmed it. We pitched Stockfish 7 with the REBEL book against the book of 2 times YAT winner Andscacs and the result was convincing.


SF7 (ProDeo.bin) - SF7 (varied.bin) 111.5 - 88.5

3.5 Mb

Click to enlarge



As second step we added the analysis work of Dann Corbit and Les Fernandez to the ProDeo.bin book. This has resulted in a Polyglot opening book with 111 million moves. This book did very well in the YAT-2 tournament.


Another 200 game match, now with the Noomen Corbit cocktail also ended positive.


SF7 (DC.bin) - SF7 (varied.bin) 109 - 91


Approx. 700 Mb

After unzip 1.7 Gb

Polyglot Books can be edited by Winboard and Scid.


Realize that making changes to the big DC.BIN book the saving may take considerable time.



Third step

adding even more to it


Now as in ProDeo YAT we want to enrich the 2 (above) Polyglot books (ProDeo.bin and DC.bin) further with the valuable data of CCRL 40/40 games played by high rated engines. For that purpose we have created 7 elo based polyglot books from the CCRL data, elo 3200, 3150, 3100, 3050, 3000, 2950 and 2900 and merged into ProDeo.bin and DC.bin. To clarify, the elo-3200 book only contains data from 3200+ rated engines, the elo-3150 book only contains data from 3200+ rated engines, etc. resulting in the following updates of the ProDeo.bin polyglot book.





Used CCRL games


46 Mb

104 Mb




36 Mb

80 Mb




29 Mb

65 Mb




21 Mb

46 Mb




12 Mb

27 Mb




8 Mb

17 Mb




4.6 Mb

10 Mb



It's important to carefully consider what book to use. If you have (want to use) a 3000+ elo rated engine and you take ProDeo-2900 as opening book that might turn out not so wise because it might play moves from 2900 rating engines also as book move. It makes more sense to use ProDeo-3100-3150-3200. A safefy margin of 100 elo is adviced although it's a educated wild guess. Only testing will tell.


Therefore, for top-engines (although not impossible) it will be much harder to profit from the CCRL data, for average and lower rated engine there is a lot to gain, funny enough, the weaker your engine the more gain there is.



Updating DC.BIN

The big 111 million position opening book

with the CCRL data


The same (above) rules apply.





Used CCRL games


722 Mb

1.70 Gb




715 Mb

1.68 Gb




713 Mb

1.67 Gb




711 Mb

1.67 Gb




709 Mb

1.66 Gb




708 Mb

1.66 Gb




708 Mb

1.66 Gb



Remark regarding strength: It's reasonable to assume the ProDeo (CHT | EBF) approach will be somewhat superior to the Polyglot way of doing things as 1) they always pick the best move available from the available book moves while Polyglot picks a random move based on the "weight" value and 2) Polyglot opening books lack learning as I have understood.





Last step

conversion to Chessbase [*.CTG]


This is a do it yourself job. Select your favorite Chessbase | Fritz book and add the analysis work of Dann Corbit and Les Fernandez of 111 million positions to the *.CTG book.

Old Fritz interface

Edit -> Opening Book -> Import games

Click to enlarge

New Fritz interface

Analysis -> Opening Book -> Import games

Click to enlarge

The 111 million positions are split into 13 parts because Fritz has a PGN limitation of approx. 9.5 million games (positions) and thus after unzipping the download you will see 13 PGN files. The first 12 (dc.001.pgn - dc.012.pgn) contain each 9 million positions, dc.013.pgn 3.2 million.


Import each PGN to the loaded Fritz book (see the pictures), it will take about 15-30 minutes depending on your PC and you will notice that after each import the Fritz book has increased with approx. 1 Gb in size. This is no typo, if the job is done you will end up with an opening book of 13-14 Gb. Really...

Check it out


To check if the book is okay and the position are in paste the below EPD strings into Fritz and see if the position and move are available. The below 26 positions represent the first and last position of each dc.001.pgn - dc.013.pgn.


Approx. 1.2 Gb

The above positions should be also visible in (and playable from) the (above) Polyglot DC.BIN opening book.


And now I have enough,

besides my hard disk needs a rest as well.