IS STOCKFISH THE BEST FREE CHESS ENGINE?

According to the CCRL 40/40 list Stockfish is the second best chess engine of any type. It is the best open source, free chess engine by five places in this list.

In the future, I hope to play Fire 5, Andscacs 0.88, Fizbo 1.9 and Equinox 3.2 in chess tournaments of their own soon, but for now, this chess match is restricted to free and open source chess engines only. Open source is good for the development of these engines overall as it allows newcomers to learn from the best. I want to support this.

CHOICE OF CHESS GUI

For the “match” tournament interface I chose to use the excellent Aquarium 2017 chess software. I could also have used the free Arena Chess GUI, but as I have just bought the update of Aquarium 2015 to Aquarium 2017 it seemed like a good excuse to use it. The update, which is cheaper than the full version, was only £22 (about $25)  – bargain! Aquarium also has a native setting which makes starting a chess engine match at FIDE Classic time controls really, really, easy. Anyway, we have a “venue” and two competitors, so what about the rules?

WHY CHOOSE LONG TIME CONTROLS?

A good reason for using long time controls is that absolutely everyone runs blitz chess tests. There seems little point in posting a blitz chess match that almost anyone can recreate in ten minutes. Be honest, if you have previously bought a computer chess program like Fritz, running an engine competition was one of the first things you did, wasn’t it?

Be honest!

Another issue is that the difference in playing strength between these two chess titans virtually guarantees the result. For this reason, a chess engine competition like this cannot truly be called a “test” as the result seems certain. Rather, it is a free chess engine match, between two world class chess opponents. If this was a F.I.D.E. rated world championship competition then, of course, it would take place at long time controls – e.g. 2 hours for 40 moves (FIDE Classic).

Playing chess at long time controls takes a lot of computer time. Fortunately, I have just bought a new MacBook Pro which means my old i7 PC is largely free these days. The old Windows PC is four core and so is compatible with normal computer chess ranking standards. These chess games took nearly a week of 24 hours/day computer time! Something that was not possible for me until recently as my PC was also my work computer.

Long time controls allow Stockfish to regularly evaluate 30-35 ply ahead. Gull manages roughly 25-30 ply with the same time available. I thought it might be interesting to see if the difference in ply depth analysis would be more telling, or whether a shallower depth and perhaps better overall analysis would win the day?

CHOICE OF CHESS OPENINGS AND OPENING BOOK

The chosen opening book was “NarrowBook” which is optimised for chess computers. Perhaps I will update it at some point as it is at least three years old and theory may have moved on, but for now it should be fine. Opening book knowledge was restricted to 12 moves, although the computers were regularly out of book before that point.

The match was configured to make the engines play the same opening as black and white. Although restricting the choice of opening moves is somewhat artificial, I thought it was a worthy sacrifice as it enables us to see if the victory in a given game was due to playing strength, or opening advantage. Any free chess engine will have a question over its quality of analysis for some. As both programs use open source code we know their evaluations will differ, but I hoped for some insight into the quality of evaluation given the extra time.

The chess openings chosen by ECO code and English description were:

• B43 – Sicilian, Kan, 5.Nc3
• B92 – Sicilian, Najdorf, 6.f4
• B97 – Sicilian, Najdorf, 7…Qb6 (poisoned pawn variation)
• D48 – Queens Gambit Declined (QGD); Meran, 8…a6
• B33 – Sicilian, Sveshnikov (Lasker–Pelikan) Variation, 2.Nf3 Nc6 3.d4 cxd4 4.Nxd4 Nf6 (without 5.Nc3 e6 (B45) 5…g6 (B34) 5…d6 (B56))

I am in two minds about the wisdom of letting the chess software randomly choose from a limited opening book. While Sicilians are a commonly played chess opening, my intention was not to have four of five games include them. Four semi-closed games and only one semi-open is hardly a wide variety. Chess computers excel at chess tactics, a few open games would have been interesting. At some point in the future I will repeat this match and in future, all chess engine matches will utilise these different settings.

Lesson learned!

STOCKFISH 8 vs GULL 3 – THE RESULTS

Stockfish managed to win 3 out of ten games, with seven draws.

First of all, let me say that Gull is a very good chess program. Unfortunately, here it is simply outclassed. This result is not a surprise.

Indeed, if Gull had managed to take a point off Stockfish then that would have been very interesting. Does this near unbeatable free chess engine have a weakness after all? If it does, these games did not find it.

Let us not be too picky though. One thing to remember is that either free chess engine is far better than any human chess player, even chess grandmasters. They would both be an excellent tool for your own chess improvement.

RESULTS TABLE

FREE PGN DOWNLOAD OF STOCKFISH VS GULL

For anyone that keeps a chess database I have made the PGN download available. The file is zipped down to 30k. Any unzip program should be able to open it. While both the machine this file was created on and this server are both regularly virus checked, do please run a virus checker on any file you download.

Stockfish 8 vs Gull 3 – free pgn download (zip)

All ten games. More free chess engine tests coming soon!

Computer Chess Online - Stockfish 8 vs Gull 3 Free Chess Engine Match

What also might not be commonly known is that whenever the code for these free chess engines is publicly available Jim will also recompile the code to run more efficiently. Jim’s recompiles of well-known chess engines often run better than the original chess program did!

Have a look at Jim’s work at: http://jimablett.hostwebs.com/ (no longer valid)

Edit: Jim’s site moved again and he has retired from his compilation work – a sad loss.

The final repository of Jim’s work is at: http://jimablett.net63.net/ (Edit: Sorry this link was later found to have 4(!) trojans in the download. I have removed the active link, but leave the location as anyone with an up to date virus scanner may still wish to visit).

(The old site at: http://homepages.tesco.net/henry.ablett/jims.html is no longer maintained.)

It is a testament to the quality of the work that Jim does in his recompiles that many of the authors of many free chess engines are now going to him to have their code “tweaked”.

So, if you are looking for free chess software in the form of winboard or UCI chess engines then Jim’s page is a good place to start.

Some of the files he hosts include (no particular order):

• Rival Chess
• Red Queen Chess
• Protector
• GNU Chess
• Simplex
• Greko
• Komodo
• Gez
• Mizar
• Sjeng
• Scorpio
• Chess One
• Crafty
• Beaches
• Fimbulwinter
• Sungorous
• Alibaba

And many, many more.

Stockfish – Free Chess Engine

As a separate word of note.  Jim also compiled the latest version of Stockfish.  Stockfish is a free chess engine that is now within a few Elo points of Rybka 4 (currently the world’s strongest chess engine).  This is a great achievement by the team behind Stockfish and it must be mentioned that they deserve full credit and the thanks of the community at large for making a chess engine of this quality freely available.

If for some reason the download is offline you can get the Stockfish chess engine from: https://stockfishchess.org

Also, take a look at the custom made opening book to suit the engine’s particular style of play.

About UCI and Winboard Chess Engines

Winboard and UCI compatible chess programs do not run on their own.  You need a GUI to operate them.  Thankfully there are a number of free chess interfaces available.

My personal recommendation is Arena – which is hosted at: http://www.playwitharena.com/

Full explanation of the various parts of the install is dealt with on the site and Arena even comes with an early (and free) version of Rybka.

Of course if installing all these bits of software is not your thing then feel free to try out our free online chess game here at computer chess online.

Happy playing!

Computer Chess Online - Jim Abletts Free Chess Engine Site has Moved

Free Computer Chess Game for Visitors

We live in the computer age yet many people have never played chess against a computer.  I guess there are as many reasons for this as there are people in this situation.  As I enjoy computer chess I thought it was only fair to offer other people the chance to indulge themselves in a game I enjoy.

Although a number of sites like The Spectator offer chess puzzles online they do not offer the chance to play a full game. Here is my small effort toward improving the situation.

Installing Flash CHESS 3

Now don’t laugh, but it took me a few days just to get the page working.  The people from flashchess made a great program. However, my complete ignorance about how to install it on a website stood in my path quite some time.  Eventually, I found a way to install chess program and get it to work within WordPress. Overall I am happy with the results. The sole niggle is page load time. This is unavoidable as the computer engine has to load the game to work (about 2megs total).

It was my original goal to make a variety of chess computers available. Unfortunately, there was little interest from programmers in showcasing their work.  This left me with an unusual chess problem to solve. The only chess engine I could hope to put on the page was one that was freely distributed.  Flash chess 3 is thankfully a pretty advanced program considering its size. It looks good and plays reasonably well. And all this considering that it was written in Flash rather than a more conventional programming language.

If there are any computer chess programmers out there reading this with a non-experimental chess engine that can run within a web page please contact me.  It would be really great to offer people a greater variety of chess software and let them see what is available.

Installing Chess Programs is Fun! (Honest)

Anyone that is familiar with my other websites will know already that I am a big fan of computers and technology, science fiction, chess and online games in general. Writing this website is a labour of love. Yes, even when I can’t get annoying flash chess programs to install and run properly on it!

I hope over the coming months to show people some of the things that are really great about the game of chess in general, and computer chess in particular.  For now, though, I hope you enjoy your time here and this opportunity to play free online chess against a computer.

Computer Chess Online - Play Free Online Chess Against a Computer