• Overview

Rebel 10 is the latest in a long series of chess programs produced by Holland-based Schröder BV. So far, Rebel has been a very successuful chess program. It has won the strong Aegon tournament, pitting against each other strong grandmasters and strong chess programs. In 1997, Rebel also won a match against the strong GM Artur Yusupov, and another match in September 1998 played with GM Visnawathan Anand, who is currently considered the second-best player in the world just behind Garry Kasparov.

Rebel has earned a reputation for having a playing style very much reminescent of human players. It plays a strong positional game while also keeping the position dynamic. Version 10's chess engine has been completely rewritten and is tactically stronger. It also features a new Anti-GM option which makes the program play for even more dynamic positions. Other enhancements include a new user interface with resizable windows and user-customizable layouts, a large database containing 300,000 games and the EOC, a 16 million-move chess tree based on the database that comes with the program. The opening book and database functions have also been considerably improved.

• General impression

Like Rebel 9, Rebel 10 is easy to use. The various menus are clearly laid out and the great number of options available, easy to select. The program offers the user the possibility to access the program options through three basic setups: Novice, Intermediate and Expert. That way, a chess player already familiar with Rebel 8 or 9 can select Rebel 10's Expert option and have access to all the possibilities available, while a newcomer can select the Novice option to access only the basic options needed to operate the program, until he gets more familiar with its operation.

The chessboard and pieces in Rebel are the best I have seen so far among the various DOS-based programs. On that aspect, In my opinion, on that aspect Rebel even compares favorably with Windows-based program like Fritz or Genius. Rebel chessboard and pieces are easy on the eyes and permit the user to play a game or analyze for several hours without problems.

Compared to version 9, Rebel 10 has a completely revamped user interface. The general "graphical" impression is quite good and the various windows are now fully resizable and can also be moved. The chessboard can also be adjusted to several sizes. The program comes with various well-done predefined layouts that can be activated through the keyboard. The user can also configure and save his own layouts.

However, there are some limits. Although the windows can easily be moved with the mouse, the rezising cannot be done with it; the user must go into the Layout menu and choose between various predefined options, e.g. choosing the number of line of information that will be presented in a given window. I have also noticed a few minor graphical glitches here and there. For example, when the program is analyzing an opening book and the Warroom is enabled, the information displayed in the Warroom window gets garbled. That garble also affects the "game searched" line at the bottom of the database main window when searching for games. The EVALUATE button at the right-down corner is also affected. These are very minor problems that will hopefully get fixed in the Rebel 10a patch to be soon released.

Overall, Rebel 10 offers the user a very good interface, easy to use and configure.

• Playing strenght

Nowadays, the top chess programs are so strong that they can easily defeat everyone but the strongest of players, those at the very top. As I am rather a novice player (ELO 1240), I am unfortunately not in a position to judge accuretaly if Rebel 10 is much stronger or not than its predecessors, but based on the various comments I have seen and heard, on other reviews and from the match played against GM Anand, Rebel 10 certainly gives the impression that it is very strong indeed, more tactically alert while playing more dynamically than Rebel 8 and 9.

The chess engine features a new option called Anti-GM, that enables the program to seek positions that are more dynamic and unbalanced, therefore making life more difficult for human opponents while keeping the sound human-style positional play that has made the reputation of the Rebel chess programs. The Anti-GM option can be set at various settings of activity (smart, strong and active), or it can be deactivated if the user wants the program to play in a more conservative positional style.

Also new to Rebel 10 is the EOC (Encyclopaedia of Chess), a chess tree based on the 300,000-game database that comes on the program's CD-ROM. The Rebel 10 EOC comprises 16 million positions and offers the possibility to see what are the best moves to be made in a given position, particularly in the opening. Among other things, win-draw-lost statistics are available for each moves, making it easy to see what are the best choices or the more successful ones. Rebel can use the EOC in various ways to assist its search and it can also use it as an opening book. The EOC CD-ROM, a separate product based on more than one million games and featuring 50 million position, will be usable with Rebel 10.

Despite being very strong, Rebel 10 does offer some chances at salvation to the user. There are various options available to weaken the program, like three playing strenght choices (Strong, Intermediate, Novice) and a very useful ELO Setting option. If the Novice level is rather too easy to play against, the Intermediate level does offer a strong opponent to play against. However, the ELO option is the best way to adjust the program and seems surprisingly accurate. I have tried it several times at 1300, and despite the fact that the program did beat me, the games were very close and usually their issues were determined by a blunder... ;-)

One aspect where the strenght of a chess engine comes handy is when analyzing games or positions. Rebel 10 offers all the necessary features on that aspect. One can analyse an entire game overnight for white, black or both sides, use include or exclude move options to dig deeper into a position or enable continuous analysis while replaying a game to see what the program thinks about the position at every move. One feature missing is a contempt factor option.

Five different style of play are available, from agressive to defensive. Together with the settings available for the Anti-GM option, they enable the user to program different playing styles in Rebel 10. However, I think that this is not enough and that Rebel misses more elaborate and adjustable chess engine parameters, like the ones found in ChessMaster or M-Chess Pro, for example. Being able to play with various adjustments like piece value, pawn structure, king safety, activity, etc., a user could define much more elaborate playing style, thus increasing considerably the sparring-partner value of Rebel.

Other features new to Rebel 10 chess engine are more time controls, like a new blitz Fischer mode, and a redesigned Combination option that enables the program to find the key move faster in chess tests and problems.

• Database

Rebel 10's database offers many possibilities. Among several useful features, in the game list window (the main one) two small board can be seen at the right of the screen, showing both the opening position and the final position for any selected game. An Overview button at the bottom of the screen also offers a global vue of the selected game on several small chessboards. At the right-down corner of the window, a big EVALUATE button gives the possibility of analyzing briefly the final position. PGN files can be handled easily, although the options offered are very basic; but they can be easily imported into a Rebel-format database for more elaborate operations.

Two new important additions to Rebel 10's database are the new free index and the search mask. With the free index, the user can use any information he wants as a game classification criterion. As for the search mask, this is a well-needed addition that enables the user to perform much more powerful searches than what was possible in Rebel 9. Almost all important searchable items are available with boolean operators: player's name, date range, opening, etc. Four small boards also offer several search possibilities: moves, position, pattern and material.

Despite the fact that Rebel 10's database is not very fast when performing a search (when compared to Chess Assistant or ChessBase), its features and ease of use make it one of the main strenghts of the program. It is certainly one of the most featured-filled databases offered in a chess program.

There is one very important feature still missing in Rebel 10's database thought: the possibility to save embedded variations and comments in a game. Such a feature is really a must nowadays in any chess programs. Lets hope that the next version of Rebel will be such equipped...

• Book functions

Along with a bigger opening book armed with the latest theoretical wrinkles, new lines and containing more than one million moves, Rebel 10 has many features for opening repertoire afficionados who want to work on that aspect of their play.

For example, specialized books can be made from any database and can then be edited and analysed from within the program. Several books can also be joined together to form a bigger one. Rebel 10 can also import books from the ChessMaster, Genius and Fritz programs. Schröder BV offers an Internet subscription service on its WWW site to any Rebel 10 buyers, where they can get their hands on a very nice collection of analysed opening books for all the major opening lines, along with the possibility to download several useful utilities.

If there is one aspect where Rebel 10's opening book implemetation could be improved, it is in having some feature to weaken how the book is used by the program. As it is now, Rebel 10 always uses an opening book "as is", to its full depth. What use is it to a novice chess player to play a program weakened to an ELO level of 1200 when it still has grandmaster-strenght in the opening!!? In my opinion, the sparring-partner value of Rebel would be greatly improved if the book use could be weakened somehow. One possibility would be an option to limit the depth at which the program can look in a book, thus limiting its knowledge.

• Other aspects

Along with its feature-rich database and various opening book options, Rebel 10 offers other interesting features.

For those interested in comparing the strength of the various versions of the Rebel chess engine, Rebel 10, like its predecessor, offers several options to let the many incarnations of Rebel (from Rebel 7 and Rebel Decade to Rebel 8, 9 and 10) compete against each other in matches, using different books, strengt setting, style of play and time control via the two NAME menus.

Other features include the possibility to play simultaneous games against several Rebel opponents, various Energy Levels where Rebel plays with either increasing or decreasing strenght, Blindfold play, and Fun Levels where different penalty are imposed upon certain types of move.

Despite the fact that these various options are more related to leisure than serious study, they do increase the potential of the program and often offer pleasant playing alternatives.

• Pro

* One of the strongest chess engines available, playing a sound positional style while also seeking active unbalanced positions.

* New EOC chess tree and 300,000 games database.

* New user interface, easy to use, completely customizable and with nice predefined layouts.

* One of the best chessboard-pieces design on the market.

* Feature-rich database with powerful new search mask.

* Many opening book-related options for the opening afficionado.

* A free Internet subscription service offering many interesting things to download.

• Con

* Some minor graphical glitches.

* Not enough options to modify the way the chess engine plays (piece value, king safety, pawn structure, attack/defence, activity, etc.).

* No options to save embedded variations and comments inside a game.

* No possibility offered to weaken the way Rebel uses its opening book. Its not very easy to play a ELO 1200 computer opponent that still has a grandmaster's opening knowledge.

• Recommendation

For the serious chess player, Rebel 10 is definitely a choice to consider. Recommended.