AFAIR it works by storing the most likely human move for every 3 move sequence e.g. "St Pa, St Sc, St St". If we assume most players play similarly, and don't

AFAIR it works by storing the most likely human move for every 3 move sequence e.g. "St Pa, St Sc, St St". If we assume most players play similarly, and don't remember much more than the last three results, this works really well.