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October 9, 2000    GAMBIT TIGER... breaking news (!!)  

TWO versions of Chess Tiger will be available on the REBEL 11.0 cdrom:

• The traditional Classic Tiger which is estimated 50-70 elo points stronger than its precursor.



• A Gambit version of Tiger which plays a whole different game of Chess using a new king safety concept. Gambit Tiger is able to play all kind of gambits much better than the Classic Tiger. Gambit Tiger will be offered as a separate engine which you can load under Options -> Engine.

The Gambit Tiger is estimated in the range of +/- 20 elo points in comparison with the Classic Tiger. Gambit Tiger is not claimed to be much stronger than the Classic Tiger as too less data is available at this moment. What is clear is that Gambit Tiger plays an aggressive type of Chess seldom seen by a chess program. Below is one of the very first blitz games Gambit Tiger played.

[Event ""]

[Site "?"]

[Date "2000.09.23"]

[Round "00923GE4.PRT"]

[White "Gambit Tiger 0.95"]

[Black "Genius5"]

[Result "1-0"]



1. d4 c6 2. c4 d5 3. Nf3 Nf6 4. Nc3 e6 5. e3 Nbd7 6. Bd3 Be7 7. O-O O-O

8. e4 dxe4 9. Nxe4 b6 10. b3 c5 11. Bb2 Bb7 12. Qe2 cxd4 13. Nxd4 Nc5

14. Nxc5 Bxc5 15. Nf3 Rc8 16. Rad1 Qe7 17. Ne5 Ba3 18. Ba1 Rfd8 19. Qc2 Qc5

20. g4 h6 21. h4 Qe7 22. g5 hxg5 23. hxg5 Ne4 24. f4 Nxg5 25. Kh2 Bd6

26. Qe2 Nh7 27. Qh5 Nf6 28. Qh3 Qc7 29. Rg1 Qc5 30. Rdf1 Qa5 31. Rf2 Ra8

32. Qh6 Bf8 33. Qxf6 Rd7 34. b4 Rc7 35. Qh6 Be4 36. Bxe4 g6 37. Qh8+ Kxh8

38. Nxg6+ Kh7 39. Nxf8+ Kh6 40. Bg7+ Kh5 41. Bf3+ Kh4 42. Bf6+ Qg5

43. Bxg5# 1-0

October 9, 2000    GAMBIT TIGER wins the French Computer Chess Title  

Yesterday Gambit Tiger conquered the French Computer Chess Title in a convincing way. Gambit Tiger remained unbeaten and only gave away 2 draws (+7 =2 -0). Gambit Tiger played on a simple Pentium II 500 Mhz while most of Tiger's direct competitors had much faster hardware (up to 1000 Mhz).

The final result:

                       1 2 3 4 5 6 7 8 9 0

1   Gambit Tiger 0.95  * ½ ½ 1 1 1 1 1 1 1   8.0/9

2   Chess Wizard       ½ * 1 1 1 ½ 1 ½ 1 1   7.5/9

3   Dragon 3.14        ½ 0 * 0 1 1 ½ 1 1 1   6.0/9

4   AnMon 509          0 0 1 * ½ 1 0 1 1 1   5.5/9

5   ZChess             0 0 0 ½ * 1 1 ½ 1 1   5.0/9

6   Chess Guru         0 ½ 0 0 0 * 1 1 1 1   4.5/9

7   Nejmet             0 0 ½ 1 0 0 * 1 1 ½   4.0/9

8   BBChess            0 ½ 0 0 ½ 0 0 * 1 1   3.0/9

9   Xie Long           0 0 0 0 0 0 0 0 * 1   1.0/9

10  Small-C            0 0 0 0 0 0 ½ 0 0 *   0.5/9

October 9, 2000   Rebel Century also for Windows (2)   

You can now run Rebel and Tiger at the same time and compare the 2 engines.

Click on the picture to enlarge.

The Rebel engine under Rebel-Tiger II will support:

• Run simultaneously with Chess Tiger playing your games or analyzing positions.
• Flexible hash table support.
• Logfile support as in Rebel Century 3.0
• Analyze Game as in Rebel Century 3.0

September 10, 2000   Rebel Century also for Windows   

The Rebel Century engine has been ported successfully to Windows. As a result the Rebel engine will be offered also under the new Rebel-Tiger User Interface but is limited as an analysis module REBEL-ECTOOL alike.

To summarize REBEL 11.0 you get THREE chess programs!

• REBEL TIGER II
• REBEL CENTURY 3.0
• REBEL CENTURY 2.0 analysis module for REBEL TIGER II

Later the REBEL CENTURY 2.0 analysis module for REBEL TIGER II will be upgraded to version 3.0 and will be offered for free via REBEL SUBSCRIBE for those who have purchased REBEL 11.0 and have subscribed.

September 10, 2000   Rebel Century 3.0 games for download

The new Rebel Century 3.0 played 353 autoplayer games against various computer opponents. Games are now available for download.

Based on the good results the engine has been frozen which means that no more changes will be made and that the released version of Rebel Century 3.0 will be the exact version that played so well in the world championship in London (August 2000) and got the bronze medal (3th place).

August 4, 2000   CAT (Computer Analysis Tool)

CAT is a new type of database similar to the EOC approach. While EOC chess trees focus on human games CAT is a chess tree for computer analysis only. CAT is "the" way to organize your computer-computer databases (games and/or positions).

CAT trees can be easily created from a Rebel database. A CAT test database made from SSDF games mainly and enriched with games from other sources will give the following informations:

Picture-1 : a typical Sicilian opening. Rebel Century 1.2 played 6.g3 exactly 5 times and scored 60% in this opening. The move 6.g3 is in all program's opening book. The CAT database contains 99.033 unique positions. 20.643 positions were found in the program's opening books. The average ply-depth of all programs in the CAT database is 12 plies deep. For "Book Hits" and "Engine hits" see further.

Picture-2 : scrolling one page down in the CAT info window gives the totals for each engine in the CAT database. For Rebel the totals are a total of 8932 positions of which 1578 are played from Rebel's opening book. Furthermore Rebel's average ply-depth was 10 plies deep based on all games.

Picture-3 : example of a game played between Rebel Century 1.2 and Fritz 5.32 while both programs have left the opening book. The move 12.Qd2 is played twice, Rebel having won twice. The ply-depth, score and main variation is also given for 12.Qd2. The latter is only possible with Rebel-Century and Rebel-Tiger as these 2 programs are the only ones that write the full main variation to stored games. With other programs the depth, score and the move played is visible.

Picture-4 : is perhaps the most fascinating option of CAT databases. When a position is found in the CAT database it will use the information and most of the time Rebel Century 3.0 is able to compute one ply deeper because of that. The screenshot shows this in action, within a few seconds the fist 11 plies are done and Rebel is going one ply deeper.

The engine when information is found in the CAT database mainly will rely on Rebel's own analyis but the engine (on request) will also use the data of other chess engines. When this option is activated Rebel is happy to play from other opening books (in this way being always longer in the book than the opponent!) or use the information of other engines as a guide line for its own decisions.

When Rebel plays a book move from another opening book than its own the counter "Book Hits" is incremented. When the Rebel engine uses an entry from the CAT database for its calculations the "Engine Hits" counter is incremented. See Picture-1.

Organizing positions with CAT   

Besides storing games in a CAT chess tree you can also import positions (test suites) in a CAT chess tree with analysis from several chess programs and compare the results to make up your mind which engine does the best job in a particular position. 3 examples are given.

Picture-5 : the critical position of game-7 of the Anand-Rebel match in 1998. Rebel 10.0 was too greedy and collected the material gain with 1...Bxb2+ not realizing Anand could escape brilliantly 10 moves later with a draw. The winning move 1...Qe6! which increases the pressure on the white king even more is no problem for Rebel Century and Rebel Tiger.

Picture-6 : 1. Bxd6! is a fine long-term positional sacrifice that exposes the black king to a decisive king attack by white. Rebel Century 3.0 seems to be the only program that gets the idea.

Picture-7 : one of the critical positions of Rebel's first game in the GM challenge against GM Michael Rohde. Rebel then played 1.exd4? where 1.Rxb4 is the much better move. Apparently this is still a difficult move for many chess programs. Even Rebel Century 3.0 needed 12 plies to see that Rxb4 is the better move.

Automatic learning with CAT   

Each game you play or every position you analyze is automatically stored in a special CAT chess tree called REBLEARN. There are several advantages for you the end-user but also for the Rebel chess engine.

REBLEARN can be seen as the graphical representation of learning. If for instance the statistic for 1.e4 c5 2.b3 is only 25% after 4 games (so 1 draw) Rebel will lower the priorty of 2.b3 in the opening book. If the move 2.b3 is played after all because of the random nature of an opening book Rebel will deal with the problem later in the game.

The advantage for you the end-user is that you immediately can see the Rebel score of each particular opening (number of games + the percentage) you have played since you have installed Century 3.0 on your hard disk. If you have a bad score against Rebel with 1.d4 Nf6 then just try 1..d5 for a change.

Picture-9 : an example made from the 353 games played against various computer opponents shows one of the critical positions of the Najdorf defence of the Sicilian. White has many posibilities. The statistic show how well (or bad) Rebel did.

the REBLEARN option can be turned on or off. REBLEARN can be emptied too (clear learning).

CAP support   

CAP stands for "Computer Analysis Project". CAP is the initiative of Danniel Corbit who with his team has analyzed over 1,000,000 positions on very long time controls. The second nice thing about CAP is that all analysis contains the main variation of each engine. The one million CAP data is full of positions of well known computer test suites. An example:

Picture-8 : a position from the famous LCT-II test suite. The position is found in Dann's 1,000,000 CAP data for Rebel and Crafty and Rebel Century 3.0 retrieves the key-move 1.Bb4! immediately from the database.

The latest data of Danniel Corbit's project (over 1,000,000 positions) will be available on the REBEL 11.0 cdrom. Updates are available from Dann's pages (or via the "REBEL Subscription Area") and easily can be added using the option "Import EPD to CAT".

I want to know more, move me to the Computer Analysis Project pages.

Creating and maintaining big CAT chess trees   

Creating CAT chess trees is easy and various data input possiblities are at your service, such as:

• Output from (any) auto232 games (the SSDF games comes to mind).
• Output from Rebel's engine-engine matches (by playing many matches you automatically make Rebel a bit stronger!)
• Output from the popular ChessBase engine-engine matches.
• Using suitable EPD files such as the CAP data from Danniel Corbit or the output from Rebel's function "Analyze EPD".

Many tools to create and maintain CAT chess trees are available:

• Create a new (and empty) CAT database.
• Load a CAT database.
• Import CAT via Rebel databases.
• Import CAT via EPD files.
• Merge CAT (merge 2 CAT databases into 1).

"Merge CAT" is extremely handy for auto232 lovers. Every time you have finished an auto232 session with Rebel Century 3.0 just merge the automatically created REBLEARN into the CAT database of your choice.


Providing data to build your own CAT chess trees   

Planned for the Rebel 11.0 cdrom are the following CAT databases:

• All suitable public computer-computer games provided by the SSDF (*)
• A default REBLEARN database from all auto232 games Rebel Century 3.0 has played.
• Danniel Corbit's 1,000,000 positions stored in CAT.

Plans for the Rebel Subscription Area are:

• When available provide updates for the SSDF CAT database (*)
• When available provide updates from Danniel Corbit's project.
• When available provide updates for REBLEARN.
• Open a section where users can submit own made CAT databases and exchange them.

* Maintaining the SSDF games database is the work of Tony Hedlund one of the leading SSDF members. Tony's work and databases can be found on his pages.

Source: Rob Kemper, REBEL GUI programmer and Ed Schröder, author of REBEL.

August 3, 2000   Engine improvements REBEL-TIGER.

• The search algorithms have been improved. Tiger now computes deeper.



• Better king safety evaluation.



• Generally speaking, the engine has been optimized and can compute faster. This speed gain has been used to add more knowledge. The result is that the upcoming engine will not be faster in NPS, but is guaranteed to understand chess better.



• The program will be less likely to lose on time in won or drawish positions.



• Several anticomputer strategies have been identified and Tiger will be able to play against them.



• Better hash table management. You'll be able to use more RAM on a given computer, and Tiger will be able to use very big hash tables even at the fastest time controls.



• A number of other improvements impossible to list but which represent months of work.

Source: Christophe Theron, author of Chess Tiger.

August 3, 2000   GUI improvements REBEL-TIGER.

NEW FEATURES:

• Name of played opening displayed independent of enginge.
• Improved book display now shows opening names of the moves.
• Customizable toolbars and menu's.
• Book independent of engine.
• Multiple books.
• All fonts, backgrounds and colors customizable.
• Borderless chessboard.
• Analyse games from databases.
• Analyse EPD files.
• EPD support.

IMPROVEMENTS:

• Increased the history size of the statistics window from 100 to 500 lines.
• During game analysis, some functions like window minimize are now possible.
• Some score outputs where not properly localized.
• Histogram has tooltips to show move and score.
• Histogram remains aspect ratio during resize, this makes it possible to show more moves.
• Internet console now set the interface variable. The value of the variable depends on the selected engine and whether the 'Computer plays' option is selected.
• The 'Computer plays' option can only be changed when there is no active session.
• When playing on ICC/FICS it is no longer possible to enable the analyse mode while playing a match. It is possible to enable analyse mode while observing a game.

INTERNET PLAY RELATED ENHANCEMENTS:

• Better font and coloring of internet console.
• Now sends CR/LF at end of move for handling at chessnet, this should allow accuclock to work properly.
• Added game start / stop decoding for chessnet.
• New sounds on game start/stop, tell, kibitz, challenge, shout, c-shout.
• Store ELO ratings in game.
• Store time control in game.
• Added history buffer in input line (up/down arrow).
• Added some command completion functions.
• Added copy and paste functions in internet console and inputline, use Ctrl+INS.
• Allows multiple seeks to be posted.

GENERAL ENHANCEMENTS:

• Printer output now in black.
• The board position is now copied to the clipboard in EPD format.
• Highlight of last move. To enable see board options page.
• Option to send multiple seeks.
• Database window separators are saved for the first database.
• Disable analysing brain option when computers plays.

BUG FIXES:

• right click while dragging piece causes hang.
• Auto232 player did not pass minor promote when extended mode was not checked, now this option is ignored.
• Histogram scale sometimes showed +- 9 , while none of the moves had a score more then +- 1 pawn.
• Increase range of allowed ELO ratings to 500-3500.
• Proper move notation in bookmoves window.
• On windows 2000 wrong move was underlined.
• BATCHCVT program was not working, fixed now !

Source: Lex Loep, author of the REBEL-TIGER GUI (Graphical User Interface)

August 3, 2000   Engine improvements REBEL CENTURY 3.0

In the spirit of Rebel Century 1.2 further improvements are made to the search algorithms. Rebel Century 3.0 now computes much deeper witch automatically guarantees better chess.

No compromises have been made to speed-up Rebel Century by removing existing chess knowledge, its 10-20% higher NPS is caused by rewriting crucial parts of the search engine and Rebel's natural playing style is kept.

The first auto232 results of Rebel Century 3.0 look good. After 353 games on 40/40 (1 minute average) Rebel Century 3.0 scored 55% which is not bad at all if you keep in mind Rebel Century 3.0 performs less well in auto232 than in manual games because the auto232 driver hurts Rebel Century's playing strength frequently.

Database: AH8-ALL   ***   Complete overview   ***



Name                  Tot      Score        +   ½   -  Perc



Fritz 5.32            102   45.0 -  57.0   31  28  43   44%

Fritz6                 52   20.5 -  31.5   10  21  21   39%

Junior 6a              43   16.0 -  27.0    7  18  18   37%

Rebel Century 1.0      68   29.5 -  38.5   10  39  19   43%

Rebel Tiger            61   36.0 -  25.0   25  22  14   59%

Shredder 4             27    9.5 -  17.5    3  13  11   35%

Rebel Century 3.0     353  196.5 - 156.5  126 141  86   55%

Remarkable is Rebel Century 3.0 huge loss against its Windows brother Rebel-Tiger. Without this form of fratricide Rebel Century 3.0 would have scored 58% which is huge against this strong competition.

Download the 353 autoplayer games in REBEL format. Games are with REBEL's annotations (500 Kb).

Further improvements are: persistent hash table which gives a speed-up of 10-15% during the permanent brain, faster hash table access, increased hash table size now up to 400 Mb.

Bugfixes: fixed the EOC bug that caused Rebel to display (and/or play) strange moves that never were played in any chess tournament, En-passant bug in Rebel Century 1.2 that caused the program to give away a pawn for free in en-passant situations, fixed the [Chess Knowledge] parameter that was inactive in Century 1.2

Source: Ed Schröder, author of REBEL.