Shredder Classic
Shredder Classic
These days, Shredder is certainly a well known chess engine. But I remember the first time that Shredder won the World Micro Computer Championship. It was said widely (and rightly so), that you couldn't tell whether it deserved the title, simply because the result was based on one tournament. Well, it's been eight years since then, and Shredder has now accumulated another seven computer chess titles. This consistently strong performance has cemented Shredder's place at the top of the heap.
Although Shredder continues to be available as a Chessbase engine, the version being sold on the Shredder website does not use the Fritz/Chessbase GUI, and instead uses its own. The "Shredder Classic" GUI, as it is called, is a model of efficiency and bug-free operation. I have watched this GUI develop since version 3, and it has never crashed on me. Indeed, it is probably the most bug-free piece of chess software that I've used.
Note that the version numbering on Shredder may be a little confusing. The version reviewed for this article was actually released in 2004, and comes after version 8 (for more information on this, see the "Engine Characteristics" section).
Now on to the rest of the review.
General GUI Elements
The Shredder GUI adheres very well to current windows standards. One thing that I liked was the way child windows are automatically resized in response to resizing an adjoining window. In most other programs, the resizing is not implemented nearly as well (the exception here is Convekta's new internet chess client), and it can result in a frustrating time trying to get all the windows on the screen at once (clock, board, move list, engine window, etc).
Generally speaking, all the important elements are present in the interface. While there are a number of different piece sets (four), and backgrounds (four), my preference is for the Shredder default piece set, and wooden board. Indeed, the best piece sets in Shredder are all 2-D. And while there is a very easily adjustable 3-D board, it does not provide photo-realistic images. It may not look pretty, but this approach does have the advantage of being fast, and thus does not require the latest hardware.
There is a game progress graph (sometimes incorrectly called a histogram), audio move notification, and all the normal functions you'd expect to see. Variations and move comments are supported too.
Engine setup is easy, and the interface is compatible with both Winboard and UCI protocols (for more information on the differences, see this link). One advantage of UCI is that it provides basic support for engine parameter adjustment via GUI controls, rather than text files. This makes engine setup much easier than in Winboard-only interfaces.
To sum up, working with the GUI is very pleasant. While it does not have a killer 3-D board, the default 2-D board is very sharp. Furthermore, you don't have to run out and buy the latest, greatest accelerated 3-D video card to get the most out of the interface.
Opening Book
Once you purchase Shredder, you can use the optional bonus opening book, created by Sandro Necchi (the initial program download does contain a small opening book, but the bonus book is much larger). The download is about 20M in size, and the book expands to about 90M when uncompressed. If you don't have broadband, I would recommend using a product called MetaProducts Download Express, which supports both multithreaded downloads and resume.
I've commented in the past about Shredder's opening book controls. They are very easy to use (perhaps the easiest of any commercial program). For instance, you can influence the weight that is given to how often a particular variation is played in practice, or how well it scores. You can also have Shredder play more classically, or in hypermodern fashion. One new feature that was not present in previous versions is the ability to clear various book learning settings. Books can also be created from game collections, as well as Genius, Rebel and old Chessbase format. There is also a 'weed book' command, which can be used to remove moves that are played only rarely.
One added extra is that Pocket Fritz owners can directly export Shredder opening books created on the PC to their handhelds. A review of Pocket Fritz can be found here.
Engine Characteristics
Shredder plays a nice solid game, and seems to understand the concept of prophylaxis more than any other engine. I currently use Shredder for 90% of my analysis tasks, and it is my "first choice" engine. This is not simply because Shredder is strong. I think more importantly, I've yet to see the engine do anything that is really stupid, and the engine plays very patiently and consistently. Stefan Meyer-Kahlen states that this engine is the 'Shredder Classic Engine', which apparently has all the same knowledge as Shredder 8, but lacks a few of the engine speed optimizations present in the latter (so it will be slightly weaker).
Of course, engine personalities are supported, with several being preconfigured for the user. For the Shredder engine, you can adjust piece values, weighting given to various positional considerations, whether hash tables are used, etc. This version of Shredder also sees the return of the triple brain feature that was in versions 5&6, but was not included in subsequent versions.
You can think of the triple brain as a referee that picks the "best" move when you have two different engines running at the same time. This referee gives an indication of the best move, along with its estimate as to how sure it is about its choice (in percent). Does it make Shredder play a stronger game? I don't know. At the strength that these engines play at, it would be presumptuous of me to judge the quality of play with triple brain enabled. However, I do have some observations to share. First of all, at the first move of the game, one would expect there to be very little certainty as to the best move (ok, so maybe it is d4). And the output of the engines bear this out - with a very low certainty of the proper move. I noticed that in instances where there was a fairly obvious positional move to be made, that the certainty of the triple brain was still on the order of a few percent. I would have expected it to be a bit higher. In instances where there is a forced recapture of material, one would expect the certainty to be very high, and it is. Positions with clear tactical continuations also have high certainties. So I think what I am getting at here is that the triple brain behaves approximately as one would expect it should. It is most useful in tactical situations. Whether it makes the program play stronger chess is a subject of debate. In any case, it is another point of data that can be used when analyzing a game, and it passes my simple sanity check.
Another interesting tidbit to note is that this approach seems to be part of a thesis project by Stefan Meyer-Kahlen. The triple-brain feature seems to be an outgrowth of the so-called "three hirn" (roughly translated meaning three heads) algorithm, the brainchild of Prof. Ingo Althofer. In the original three-hirn approach, a human is used as a referee for two engines operating in infinite analysis mode. This referee decides when a move should be made, and which move is best. However, the referee cannot make a move that is not suggested by the engines. The triple brain operates in much the same way, with the computer making the decision between the two engines, and also managing time usage and providing a indication of the move's certainty.
Shredder has won numerous competitions, including both world micro computer champion (which it has won three times), world chess computer champion (won twice), and world computer blitz champion (won twice). The world computer champion title is especially significant, since Shredder ran on hardware that was much less powerful than some of its competitors.
In case you want another measure of this engine's strength, check out the current SSDF list. As of June 2004, Shredder was at the top of the list. Of course, the classic engine will not be quite as strong, but the exact difference in performance will not be known until the SSDF tests it as well.
Analysis and Database Capabilities
Shredder supports both automatic game analysis (it will insert recommended variations and move scores into a game), as well as infinite and multiple engine analysis. A k-best mode is also supported, which allows you to look at the k-best moves. One novel analysis function is the availability of a calculated variation for every legal move in the position (of course, Shredder needs to calculate the variation, before it will be visible).
Shredder includes some rudimentary database features as well. You can do header searches (i.e.. look for a game by specific players, at certain dates), but you cannot do much more than that. So there are no position or material searches. Shredder can read and write both CBF and PGN format files, so exchanging data with other software is not a problem. Here's a power-user tip for those that get this program: You will probably notice that the default search is via a substring match. So if you search for games by Tal, you'll also get games where the first player's name is Vitaly. The way around this is to place a comma after the last name. For instance, instead of searching for "Tal", you would search for "Tal,".
This latest incarnation of the native GUI introduces a novel feature - the so-called "endgame oracle". This function allows the user to conduct "what if" types of analysis in the endgame. It is probably most useful for study composers. Conversely, it is probably not as useful for problemists, since the number of pieces is limited by the tablebases on your machine (currently, six piece tablebases are about the practical limit). The information provided by the oracle can conceivably be used instead of some endgame reference materials - again with the same caveat regarding tablebase limitations.
If I could, there is one thing that I would change, and that is the way the engine score is presented to the user. This is something that is properly called an annoyance rather than a bug. Shredder, when analyzing a game, will write the score of a move from the standpoint of the side that currently has the move. For instance, if it is black to move, and black has a better position, then Shredder gives a positive score. However, this is in contrast to most other commercial engines (Rebel, Tiger, Fritz, Nimzo, Junior, etc), which give the score of the current position in absolute terms (i.e. a positive score always means that white has an advantage). The convention of always using + for a white advantage is also intuitively obvious to the average chess player. One way around this is to use the Shredder engine in another chess GUI (like Chess Assistant), that supports an absolute (rather than relative) method for showing move scores.
Playing Controls
The big news in this version of Shredder is the control for the ELO playing level. Previous versions of the program did not allow for the control of playing strength directly (but ply depth, time handicapping, etc have always been supported). However, like all ELO handicapping controls, this one is not perfect (since I think its game is a bit strong), but at least the time usage seems to be more human-like. All the normal types of time controls are available: sudden death, fixed ply, tournament, etc. There is no FRC (Fischer Random Chess) support, unless you start playing from an EPD position.
Compatibility
Shredder supports the use of UCI engines within the Shredder GUI, and is a UCI compatible engine itself. This means that it can be used in any chess playing GUI that supports UCI. This currently includes Chessbase/Fritz, as well as Chess Assistant. Shredder also supports the latest UCI extensions, which have been requested by other engine programmers.
I believe that UCI represents the best chess engine protocol at the current moment. It supports a number of analysis features, and improved communications with chess GUIs, so that many advanced techniques become possible .Furthermore, it is not a proprietary protocol, so you are not locked in to using only the products of a specific company.
Shredder is also compatible with the DGT and Tasc electronic chessboards. Voice support is included in the latest DGT driver, and there are eventual plans to add move announcements within Shredder as well.
Other
Shredder also has the ability to log moves and scores to a text file, as a game is being played. The idea is for this to be used for live publishing of games over the web. Currently, the log file is a plain PGN file. So some additional processing (using something like VB or Perl script) must then be used to produce HTML files.
Conclusion
It is probably clear that I like Shredder quite a bit. The GUI and the engine are very solid in both playing and execution. It is a strong engine, and it makes an excellent analytical tool. UCI support is excellent, which is to be as expected, given that Stefan Meyer-Kahlen wrote the standard.
The new ELO strength setting, while not perfect, does make the program much more useful for players that are not of master strength. This version of Shredder also reintroduces the triple brain feature, which some players will find useful.
Note that this version of Shredder can only be purchased directly from the program author at www.shredderchess.com.
Copy Protection
Program download via the web, license code is received via e-mail. There is no refueling or product activation required.
