A first look at Arena

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This review is based on Arena 0.79 (beta 3), as such the release version might fix some of the flaws mentioned here.NEW! 23 June 2002 - Updated to reflect changes in Arena 0.79 beta 5, changes are reflected in the following Addendum

Also note, current versions of Arena are public release beta versions, so please take that into account when complaining about bugs.

To download the latest Arena.

For a long while, Winboard was the only free interface to support the use of Crafty and other free Winboard engines1.One of the most common complaints however is that doing so using Winboard was not easy,requiring the user to wade through lots of technical documentation to setup to set up shortcuts and read about command lines; all of which is alien, to the typical Windows user who is used to changing preferences within the graphical user interface itself.

Because of the difficulty, numerous websites have sprung up (including this one) with instructions on how to use Winboard engines. In spite of this, I would guess that the vast majority of users have not gotten beyond using Gnuchess ( and perhaps Crafty if they happen to stumble onto a site that teaches them how to do it by rote), and use Winboard mainly as a client to play online.

Arena the new interface by Martin Blume seems to be custom made to combat this problem. With it's modern slick looking interface, and the ability to load/reload Chess Engines all within the comfort of the GUI, it promises to make it easier for users who are not technogeeks2 to use Chess Engines.Added to this is some impressive display options such as a analysis score graph,adjustable windows of thinking lines, Arena has many features that equals that of commercial packages.

Screenshot of Arena
Arena - a screen shot

On the other hand, there is a group of Winboard/Computer Chess experts, who know every trick in the book on getting the most out of Winboard.Does Arena have anything to offer them? My answer as you will see later is tentative yes.

For one thing Arena is the first free interface to support the UCI protocol! 3 That alone might be worth downloading Arena for even if it does not have other redeeming features. But as we shall see there are many other advantages to using Arena.

In the following (long) review, we shall see how Arena stacks up in terms of usability and features when compared to other chess products including Winboard, SCID as well as commercial software.I will attempt to cover this review from the point of view of 2 groups of imaginary readers. The first group are users who is experienced with the use of Chess engines and probably more inclined towards the practice of running engine versus engine matchs and the second less experienced group of users who have little or no experience with Chess engines and just want to see what all the fuss is about.

Arena - Basic overview

In general, Chess software today play various functions. Some serve as databases for storing,indexing of games while others are primarily used as sparring partners as well as analysing assistants. Other types of Chess software include Chess clients for playing online and so called PGN readers/displays, which loads up and display Chess games allowing you to export diagrams/pictures.Of course, the distinction is somewhat blurred today, but where does Arena fall into the spectrum?

First let's start with what Arena is not. It's not a database (I recommend SCID for that), neither does it serve as a Chess Client currently, although it likely it will do so in the future 4 .NEW! This has being done in Arena beta 5! See Addendum for more details Where it shines though is in it's potential as a sparring partner and as a analysing tool. Another niche area, that Arena is likely to own is as a GUI good for engine testing.

But before we see how it achieves this, we need to see what I feel is the core of Arena - Setting up Chess engines.

Setting up and loading of Chess Engines

For experienced Chess Engine users, setting up Chess Engines in Arena is a breeze. There are 3 difference ways to install a chess engine, but essentially it all boils down to browsing until you get the necessary exe file and clicking okay.
Installing Chess engines is a breeze

There are other options you can add such as attaching the correct configuration file in the ini row5 , or adding necessary command lines like "xboard" in the option row, This is definitely more convenient compared to the use of Chess Engines in Winboard where you have to manually change the shortcuts or type in changes in the external Winboard.ini file.

Another nice feature is that you can load or unload various Chess engines within the GUI without exiting Arena. This was not possible in Winboard.

For beginners not familiar with command line options, setting up Chess engines is also less daunting, since they no longer have to try to setup crafty by typing lines like "wcrafty.exe /fd=c:\chessengine -xboard ", all they have to do is to select the correct exe file and everything is ready to go.

Still,I expect users who have no experience with Chess engines will probably be confused by the numerous options available such as whether to pick UCI or Winboard mode (autodetect works best if you have no idea what to choose) or whether, it is necessary to fill in author,country etc and may need some trial and error6 . But this is probably unavoidable (though perhaps here is where the diversity of options and frills Arena has somewhat works against it) , given the complicated nature of Chess engine. In the future, Arena releases will be bundled with SOS , so this will ensure at least one engine that will at least be usable "out of the box" so to speak by beginners.

Another major feature of Arena is that it is the first free interface to support UCI. This probably means nothing to people who are unfamiliar with Chess engines, but for the others this means that commercial engines like Shredder 5 ,6 etc can now be used in Arena. Unfortunately, Arena currently does not provide a default opening book like many commercial GUI (Fritz,Chessmaster,Shredder 5 etc) and this means that many Chess engines like Shredder, The King (Chessmaster) which rely on the GUI for a opening book, will not have any opening books. This is not a problem for most Winboard/UCI engines which come with their own opening books.

The Windows in Arena.

Watching Chess engines in Arena (whether in a engine match or in analysis mode) is a great experience. For one thing, there is a nice resizeable thinking window for each chess engine that displays the principle variation lines, the depth searched, the hash table filled (for UCI only) and the speed of the Chess engine in nodes per second.The last feature (and the resizeable window) is a particularly welcome when watching engine versus engine matches. Under Winboard, unfortunately,during engine matches (but not in analysis mode) you can only see part of the thinking lines of the engines.

Another nice feature includes the "permanent statistics window" which shows a nice graph with charts the rise and fall of the evaluation scores of both engines. This can also be useful for spotting gross disagreements in the evaluations by the difference Chess engines at a glance.

The move list also displays the time taken for each move (useful for various purposes such as checking time allocation,positions when the engine came out of book etc), depth searched and main line, which again is very useful information,espically for those interested in monitoring the progress and performance of Chess engines.

Some of the interesting/useful statistics displayed in Arena

However while Arena (as well as Winboard) allows you to run a series of matches between 2 different Chess engines automatically (including the option of reusing a engine after each game), it does not allow you to automatically run a round robin tournament or Swiss for example. In this aspect, Winboard users who want to run such tourneys are perhaps better off using Winboard, because it is easier for them to setup batch files to handle this, or use the external Winboard tourney managers like those by Jori Ostrovskij and Nikola Bacic This feature (together with a built in elo calculator) which is available in commercial software like Fritz, is definitely a important one, if Arena is to serve as a important tool for engine testing.

Talking about testing, Arena also gives you the ability to load up a EPD file of test positions and automatically run though all the positions and record the results in a file. This is very nice, but it doesn't keep track of the results and you will still have to dig into the analysis file (with engine analysis for each position) and count the number of correct results.

Analysing with Arena

If you are not interested in running Engine matches, Arena also works well as a analysing partner.Like most software today, Arena supports the easy import and export of games and positions in PGN and EPD and and from the clipboard.This enables you to quickly cut and paste interesting games or positions to be analysed by any of the Chess engines housed in Arena.

The disadvantage of Winboard when analyzing with engines is that you cannot instruct the engine to analyse the whole game at one shot but must manually,step through all the moves one by one. Also, there seems to be no way to write the analysis results into the game file. Arena solves this problem as it can auto-analyse one whole game (or a sequence of move if you so desire) and save all the results in the game file or in a analysis file.This is great for people who want to run analyses of their games at long time controls, as they can leave their computers running and come back a few hours later with all the analysis saved7.

While this is good, it seems that this auto-analyse feature works only for one game, and it doesn't work if you want to auto analyze a batch of games.Also unlike most commercial software (or the built in annotateh feature in crafty), you cannot set a "tolerance level", such that the Chess engine will only comment, if the difference in evaluation in the move made in the real game and the engine's preferred move is bigger than a certain level.

Another feature that is available in Arena, is the ability to step through a game with 2 engines running together in parallel. Obviously this will lead to less accurate analysis by each of the engines, but it can be useful if you feel the need to compare the analysis of 2 different engines.

Another interesting feature that you might consider using is to analyse using UCI Chess engines with the multi-PV (multi principal variant) option (the free ones are Anmon, Little Goliath and Pharaon). By right clicking on the engine and selecting "configure engine",you can change the multi-PV option to 2, which will display the 2 best lines that the Chess engine is considering. This slows down the Chess engine a lot, so is not advisable if you want it at full strength.
Setting multiPV to 2, in Goliath

Continued in Part II


1. There are other free interfaces like SCID which support Winboard engines but none designed for engine versus engine play or for playing a game versus the engine. Chess Pad and Chess Assistant light comes closest.

2. I don't think it's as difficult as many think, but someone remarked to me once he could never get Crafty to run in Winboard despite trying for a while, but had no problems with Arena.So for this user at least, Arena was a easier to use tool than Winboard for using Chess engines.

3. If you are unfamiliar with what UCI/Winboard protocols are, take a look at my articles and the following pages.

4. Getting ICS support is probably one of the most wanted features, but I doubt if and when it's implemented Arena would make a very good interface for humans to play online. Given the fact that Arena is currently very complicated, it would be difficult to add the standard features expected of a Chess Client for humans. It might become a very good interface for getting Chess engines to play online though.

5. Once you attach the relevant configuration file, for example Crafty.rc for Crafty, you can right click "configure engine" and the file that you have associated will automatically pop up in a text editor ready for edit and saving. Not as good as actually configuring the settings within the GUI, but this is not possible for Winboard engines.

6. Authors of Chess Engines can help by furnishing a init file along the lines of those required for the use of Winboard engines with the chessbase adaptor, as this will cause the settings to be automatically filled in.

7. SCID , the powerful free database can do this as well. Both also allow you to decide which moves of the game to analyse, and which to leave out.