This is actually rather interesting too see what basically created the the legendary RPG style battle system. I actually chuckled a little bit when I read where he got some influence from.
SPOILER!!:
American Football and Racing in one of the later titles.


He basically did the Battle system for the Original Final Fantasy. Also IV, V, VI, IX, Tactics, and XII.

Final Fantasy's Hiroyuki Ito and the Science of Battle from 1UP.com