(image) Embless in Xboard


> Download: Embless 0.88.1 (C source, tar.gz archive)

In the summer of 2010, I decided I should write a Chess engine. Embless is the result. It implements the Xboard Protocol, meaning that Xboard (screenshot on right) can be used as a GUI for it to play against humans, other Chess engines, or on the Internet Chess Club.

Embless runs a fixed-depth search (4-ply unless compiled differently) but with extensions in various cases. If you have enough RAM, you can launch Embless with a transposition table: try launching it as "embless --ttable 24". Embless comes with a very small opening book.

I should say that I'm not a programmer by trade or training, nor do I have any actual knowledge of Chess programming techniques, other than those I picked up along the way. I started with Naive Minimax and learned about things like Alpha-Beta Pruning later. But Embless is unusual in having no Quiescence Search, and so is more prone to Horizon Effect disasters than most.

Still, I made an account for it on the Internet Chess Club and let it play for several months, and its blitz rating hovered around the 1500-1600 mark, which is semi-respectable.