written by Jeff LaHue

Overview / Executive Summary
REBEL 8 BETA was tested on a slow 486-25MHz DOS machine and found to be (positionally and tactically) a very strong chess-playing program accompanied by handy database features--including PGN capabilities. Well-received new features include ELO-adjustable playing strength, 4 board simultaneous play, and user-generated opening book capability. REBEL 8 is particularly recommended for serious chess players seeking top program strength and multiple features.

General impression (user comfort etc.)
As a REBEL DECADE user, I found the transition to REBEL 8 to be an easy one. I enjoy having the option of using a mouse or the keyboard's cursor arrow keys for move entry--it's easier on the hands/wrists to switch between the various methods. REBEL 8 has "hot buttons" on the lower right portion of the screen. The user simply point the mouse and in one click quickly select commonly used functions such as new/load/next/same game, find position, and clipboard game access versus going up to the menus and dragging through choices. Once the user learns the abbreviated button labels (G for new Game, L for Load game, N for Next game, etc.) these hot keys certainly increase user comfort and speed in moving through the program.

I used the program on an old 486-25MHz machine with mono-VGA graphics. The 2-D chess board and pieces that REBEL uses are clear, sharp, and easy on the eyes. There is no 3-D board view...although most such 3-D views I've seen on other programs are rather disorienting.

The initial impression for this REBEL DECADE user is that REBEL 8 is stronger and has numerous extra features and capabilities including PGN-support, conversion from NicBase and ChessBase, ELO settings, simultaneous play, user opening books, and more.

The program is software protected allowing unlimited installs for personal use from the original diskettes. There are no needed dongles, no required diskette reinsertions, no required passwords--so in that sense as well REBEL is comfortable to use.

Playing strength
REBEL is very strong. Period.

One only has to look at Internet posts to find that REBEL is at or near the top of all ratings lists.

I conducted a few strength tests including the old Bratko-Kopec position tests (result 18/24: 2400+ US on a slow 486-25MHz) and a one-hour CCR test with opening books off which also seeks positional strength (result 56: 2448 US). What impresses me about REBEL is that it not only has very high tactical strength, but it has good positional strength which is lacking in most chess programs. Most of the top programs are tactically powerful, but it is in the positional arena that the top programs are differentiable. I noticed a recent rec.games.chess.computer posting of Louguet II test results. It rated REBEL in first place. It also confirmed that the positional results help separate REBEL from the pack.

One pet-peeve test I like to perform on any chess program is a King+Bishop+Knight versus lone king endgame to make sure a chess-playing program can handle this basic ending. (Many programs can't!) This REBEL 8 BETA program was able to solve it within chess's requisite 50 moves when given 15 seconds/move on a slow 486-25 machine. However, I would like to see a REBEL version with end-game database capability in the future.

Database functions
REBEL is primarily a chess playing program but it has some database functions as well--creating various REBEL databases, searching by name, text, moves, position. The database function sorts by White name but you can search for a particular name, year, text, or score result. The total number of moves in each game is not shown in the list of a database's games. The database functions are not robust like Chessbase, but again, REBEL is primarily a chess playing program. The REBEL database utility DBUTIL.EXE was not part of my BETA test. That utility is supposed to be available in the future to allow deletion of duplicates, making player names more uniform, changing players' ELO ratings, etc.

PGN (Portable Game Notation) is quite popular today--particularly amongst the Internet crowd. Fortunately REBEL 8 imports from and exports to PGN. This feature (not available in DECADE) is particularly important for those who wish to collect PGN games from the Internet and analyze them with REBEL, make REBEL opening books out of them, etc.

I did encounter some non-PGN standard issues such as REBEL 8 BETA using "ep" for en passant whereas the PGN standard uses no special notation. REBEL 8 BETA uses "" for blank PGN fields whereas the PGN Standard is "?". REBEL 8 BETA uses "1996.01.01" for PGN Standard: "1996.??.??" [Perhaps a Hastings resurgence? ;-) ] I have also lost Round number PGN fields and some ECO fields when I have imported to REBEL 8 BETA and then exported back to PGN.

In importing the recent TWIC94.PGN (The Week In Chess) file from Mark Crowther's WWW chess at http://www.brad.ac.uk/~mdcrowth/chess.html REBEL 8 BETA skipped those games preceded by a non-PGN title line. (Such lines are technically non-standard, so I would say that REBEL 8 BETA can and does successfully import PGN files.) I've also encountered some comment field truncation upon exporting to a PGN file. Over all the PGN capabilities are there and usable, but they might need some fine-tuning. REBEL 8 BETA also can directly handle NicBase files and it has a tool to convert Chessbase files to REBEL format. That is also a handy option since .cbf/.cbi files are also commonly used for TWIC reporting, Internet game file collections, etc.

I do like the Search for moves and Search position database features that seek out other games within a chosen database. In the first case, REBEL finds games in which the current position is reached by the exact same move sequence. In the second case, REBEL finds games in which the current position is reached regardless of the moves. There is no piece-driven search to find all games with Rook and 2 Pawn endings, etc.

If you are into major database manipulations/extractions/etc., you probably will still want to seek out a major chess database program such as Chessbase, Chess Assistant, etc. If however you primarily seek a strong chess playing program with enough basic database functions to get you by, then REBEL 8 should satisfy your needs.

Book functions
In addition to a large opening book available with REBEL, the program features the ability to create your own opening books from game databases. For example, I downloaded a PGN file containing games of a particular opening from the Pitt Chess FTP Site at http://www1.pitt.edu/~schach/Archives . Using REBEL 8 BETA I was able to create a handy new opening book specializing in that opening. Now I can play that opening game after game (or even 4 games at a time with REBEL 8's simul feature!) The program appears to make good random use of the various opening moves. It lists the book's candidate moves in the information window--a good feature for learning/studying the opening. The edit book features were not working in the Beta version I tested, but I understand they have since been corrected.

Similarly, one also can download a collection of a particular player's games and create an opening book. Then, you can start playing games against REBEL 8 using that player's own opening repertoire. I created such a book from a top nineteenth century player, and it is interesting to note the difference in openings played.

Remaining options
REBEL 8 has many features, so I won't be mentioning all of them. A new feature is the Simultaneous play mode enabling the user to play 4 games against the computer on 4 boards. In this mode, most of the normal options from the menus are not available. I would have liked to have more of the options still available. However, I found that you can alternatively still use the 4 board mode (without simul) so that the menu options return. Then you can choose which board to play at any given time. Since almost all of us are crushed by a program, now we can be crushed in 4 games at once! Fortunately, you can pick a lower strength setting and simultaneously play 4 "weaker" opponents if you want a chance to win.

A feature I anxiously awaited is the ELO-setting feature. I find the weaker-play modes (if any) to be poorly implemented in most programs, so I was glad to see the ELO-setting on REBEL 8. I look forward to reading other BETA testers' views on its success. My testing showed it worked relatively, but I can't comment on exact ELOs. I did set REBEL 8 BETA at various ELO settings and pitted it against other program's various strength settings and the results were relatively correct. For fun I tried setting ELO at only 1 point, but it didn't appear to play much weaker than ELO 1000, so I'm not sure about the relative ELO values. My sense is that the weaker ELO levels are more time/depth based and not blunder-based, but I'll again defer to comments of other BETA testers.

Separate from the ELO options, REBEL also has 3 strength choices: Novice, Intermediate, and Strong. My experience was that the Novice played even weaker chess than the very low ELO settings. There are also playstyle setting choices as well: aggressive, active, normal, solid, defensive. Regardless, REBEL 8 definitely has a number of adjustable options enabling the user to have some chance of winning an occasional game! This remains a challenge for today's programmers: how to create a strong program, but still provide options such that the general user can play some games at his/her rating/strength level as desired.

There is also a flexible resign feature that I find helpful. Some users wonder why many chess programs don't resign. If a program can and does resign, the user often doesn't like the evaluation level at which the computer resigns. REBEL 8 lets you turn a resign feature on/off, and you can choose various resignation levels from -1 (about 1 pawn down) to -9.99 . A suggestion would be to enable the user to type in a value here instead of only choosing from pre-defined levels.

I enjoyed the Super War room feature in that it displays the four best main variations for the given position. Most programs only show the current best-line, and perhaps an earlier-calculated best-line. It is interesting to be able to look at 4 such lines (in addition to the on-going normal analysis displays.) When studying a position, I found such information helpful in evaluating and understanding candidate moves.

There is also a handy REBEL 8 "Power" analysis feature that allows the user to dictate which moves REBEL 8 should analyze. Often one wonders "What about move x or move y here?" This feature allows you to ask REBEL 8 such questions while analyzing. I found this very handy to use while watching Karpov-Kamsky over the Internet. I was using 2 computers...I'm sure some people will be requesting a REBEL for Windows version such that REBEL can be run in the background while on-line perhaps?

REBEL 8's new energy level feature allows the user to have REBEL 8's playing strength increase during the game, or decrease during the game. I was more interested in the ELO-setting feature than with the energy levels. However, I did conduct some tests (and post-game evaluations) to verify that the program strength does indeed change in such energy modes.

For serious power users: REBEL 8 allows the user to select hashtable size as well as brute force/selection settings and evaluation styles.

A list of what "I like on Rebel 8.0".
A feature I really like is the "fixed level" (exact time per move) option. Most chess playing programs only offer "average" time per move. If you choose 5 seconds per move on those other programs you sometimes are waiting 30 seconds for a move! With REBEL 8's fixed time feature, you can set it to 5 seconds per move and it will move in 5 seconds...not 4, not 6, but 5 seconds (or whatever time you choose!) REBEL 8 also has many other time controls including the conventional average time per move. There doesn't appear to be a Fischer-type time control adding time back for each completed move.

Other aspects I particularly like and have already mentioned: REBEL's strength and high rating, the ELO option, the 4 board simultaneous play option, the opening book capability for generating user-books from games collected of a particular player or opening system, and the PGN capability. [Caveats: I do await additional reviews of the ELO option, I would like the choice to have the menus/options to remain active during simul mode as in the normal 4 board mode, I await the edit userbook features, and I would like to see some tightening up toward PGN standards.]

A list of what "I do not like".
I wish REBEL 8 could automatically analyze more than one complete game at a time (serially, with REBEL automatically saving the analysis and going on to the next game while unattended.) REBEL's Analyze Database feature analyzes the start position for each database entry/game. That is great for test suites, but I would love to see a REBEL Analyze database feature that analyzes ALL moves of each selected game for overnight analysis, etc. Although I will note that you can create an EPD file of important positions from any number of games and create a database for overnight analysis.

Since REBEL is primarily a chess-playing program and not a database specialty program, there are always additional database features one would like to see. The user can't look at a database and see the number of moves in a game. I like to be able to pick out long/short games from a database, which isn't really possible with REBEL. Some basic features like deleting duplicates aren't part of the REBEL program, but I understand they'll be available in a REBEL utility program.

In the ELO-setting mode, the program goes into a "serious" mode in which some options (hint, teacher, information) aren't available. I wish this had been left as a toggle choice. If the user sets the opponent's ELO level, this doesn't mean the user wants to forego on-going evaluation features, etc. I would point out that the (hint, teacher, information) features are available if the user chooses the Novice or Intermediate Strength settings, but they are not available if the user chooses an ELO- rating setting.

My wish list also might include some printing features (diagrams would be great) and perhaps a 3-D board (if it could be done really well!) Also, end-game data bases/access would be beneficial.

BETA bugs: I was actually expecting to have a large number of problems with a BETA version of a chess program, but that was not the case. I encountered a minor graphics bug, the book editor not working, some non-standard PGN issues, an EPD bug, and some db search problems, but hopefully all of these have already been corrected or will be corrected for the REBEL 8 commercial version.

On the other hand, I have purchased software such as Chessmaster, Kasparov's Gambit, and others (which were the commercial releases of course and not BETA!) where I wondered how they ever got out of testing (or was there even testing?)! My hat is off to the Schroder team for obviously putting in a lot of time to produce a quality product even for the BETA testers! The Schroder team was always very responsive to comments and they have been very professional in their dealings.

Rebel8 compared with other chess programs I know.
As far as chess programs, I have purchased only DOS-based programs such Chessmaster 3000, Capstone's Grandmaster Chess (a Zarkov sibling), Sargon IV and V, BattleChess 4000, and Kasparov's Gambit. Rebel 8 is by far the strongest chess playing program I have used. While those lower-priced main-stream programs try to target the bells-and-whistles market (with nauseating 3-D monster modes, etc.), REBEL 8 targets the serious players who want to own a strong chess program. While REBEL 8 can handle PGN format, the aforementioned others can't handle PGN and are consequently of no use in collecting and analyzing PGN games from the Internet. REBEL's forte is its chess playing strength, and the various comparative rating/ranking reports speak for themselves.

Recommendation
If you only want fancy 3-D graphics and sound effects, REBEL 8 isn't for you. If you are serious about chess and you want one of the strongest, most useful chess programs made-to-date, REBEL 8 is well worth your consideration. If you don't have REBEL DECADE, you should run--not walk--to the SCHRODER BV WWW area and download it. DECADE is one of the best if not the best chess game downloads available on the Internet. After using DECADE, you can decide whether to purchase the stronger, multi-featured commercial version of REBEL. If you don't want PGN capability and you don't want the strongest program available and you don't want simul play or user-generated opening books or any of the other extra features in the commercial version, then REBEL DECADE alone might suit your needs. (Again, I would like to see some of the minor PGN deviations in REBEL 8 BETA addressed.) If you are a chess internet fan who always anxiously awaits the latest TWIC and Pitt file uploads, the PGN capability alone in the commercial REBEL version makes the program worthy of serious consideration. If you seek the highest rated engine with strong tactics and good positional sense, consider REBEL 8.

Comment by the Schroder BV
In the final version of Rebel 8.0 the minor PGN issues are fixed and even improved. Rebel 8.0 will for intance also handle non PGN standard files like TWIC (The week in Chess) by Mark Crowther without any problem.

Last update August 12,1996