The Mac Chess app engine is the engine. On the (because Apple Chess is using the old Sjeng) is says: For standard chess, Sjeng's rating is probably about 2450 ELO And I'm assuming that is at its best.

Macchess For Mac

As for looking at each level, there isn't much of a way to know because, beyond the 3 moves ahead area, it starts counting in seconds, and in that realm it depends on the power of the computer. The more powerful the computer, the better it plays because it can look more moves ahead in that time. TLDR - An estimated 2450 at it's best. It's not a very powerful engine, but it can still whoop most players on it's hardest difficulty.

If you like chess, you want MacChess - it's the most popular download in AOL's Macintosh Board Games section, and it is free!It defeated a master and a near-master at the Aegon 1997 tournament.(If your Mac isn't a PowerMac or iMac, get MacChess 2.5 at:)MacChess will play against you, analyze your games for you, and make diagrams for Web pages and newsletters. It has morefeatures than many commercial Mac chess-playing programs, including high-end features like PGN/EPD support, batchposition analysis and 'next best move'.