This will always have to be an approximation, but on a Mac Book Pro with the 2.8 GHz processor, plugged in, and with the engine set to the maximum strength setting, what Elo is it? I don't have direct access to the engine as far as I know, so I can't set it up to run tests against other engines, and doing that manually would be a real pain in the neck. Does anyone know what its Elo is, or if there is another way I could find out? This is assuming that Apple wrote its own chess engine and didn't just use one that was already out there (there are plenty of free, open-source chess engines). I'm also assuming that they don't rewrite the engine with each new version of Lion.

I was really surprised to see that there was no information about this on Google, and that nobody was even curious. Chess Titans speculation is out there but there is very little on the Apple program, which is surprising, because as an expert player I can handle Chess Titans, but Apple's program is much more challenging.

I will upvote guesses, but for the best answer I'd like either the actual Elo (unlikely, since that information probably doesn't exist) or a very educated guess based on tests or some other comparison to other existing chess engines.

For those curious about comparing chess engines or chess computer strength in general, check out the Wikipedia article chess engines.

  • interesting question
    – bot47
    Mar 24, 2012 at 16:51
  • I guess no one ever checked this. You might let it play against a software with known ELO to approximate it
    – bot47
    Mar 24, 2012 at 17:01
  • You have to do a large number of those to get an accurate comparison, which would take forever since at the top level it takes a very long time to move. Such things are usually done automatically, but without access to the actual code for the engine, I can't put it into a program that would do that. Mar 24, 2012 at 17:02

4 Answers 4


The Mac chess app is based on the Sjeng engine.

A page on the Sjeng website says:

Sjeng is probably a bit weaker in bughouse than it is in crazyhouse. Most Sjeng's on the FICS have a rating of about 2000 points in bughouse, with a top of over 2200 points.

For standard chess, Sjeng's rating is probably about 2450 ELO [sic]. In suicide and losers chess Sjeng beats all but the very best humans, and will beat non-specialized programs easily.

So, according to the makers of the engine Apple uses, the Elo is around 2450 in standard mode.


From my limited testing and reading it seems to be in the 1600 - 1900 range, but of course I might be completely wrong because I don't play chess that often.

As far as I know, there's no information on what the real ELO is.


Mac Chess is based on Sjeng's engines for Mac computers. It is one of the most powerful engines in the world available. At it's highest setting it is able to achieve a staggering rating of approximately 3000+ elo. See here for references.

I can personally vouch for its strength having matched apples chess engine against that of Shredder chess engines (producing a rating of about 2700 elo on my Mac.) Apple's engine beats shredder nearly every time if the game is not a draw. It is definitely powerful.


I'm doing a little chess software league and I do have Apple Chess competing in it. I'd say 2450 is a realistic estimate for the Sjeng version Apple Chess uses, in my league is loosing 2.5-3.5 against Sigma 6.2, which is rated a little bit over 2500, and 0-4 against Chessmaster 9 (King engine), which stands over 2700; but it does lead 3-1 against Deep Junior 12 Lite ( a lighter version of famous world champion engine) which also ranks around 2500. However, the non-comercial version, Deep Sjeng, the one that competed in World championships and even won a shared title in 2009, has an ELO of 2943, according to computerchess.org.uk, the most competent site for computer chess in my opinion...

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