Description given in 2007:
micro-Max is, as far as I know, the smallest Chess program in the world. It consists of only about 100 lines of C code, less than 2,000 characters in total. The design criterion of micro-Max was not so much to write an engine of minimum size, but one that had the best strength vs size ratio. It is the only engine in existence that has more ELO points than its source code has characters. It does not use an opening book or tablebases, but its search does implement internal iterative deepening, a hash table, futility and null-move pruning, late-move reductions and a check extension.