PBMA (Pro Bike Mechanic Assoc) mentions Jis and not one US bike tool company except Abbey make it. Oh, Park Tools recently released two drivers.
JIS has a single straight edge whereas Phillips has 2 and sometimes rounded. Both terminate to a flat bottom. JIS cross tip driver will virtually fully contact a Phillips screw and yet a Phillips cross tip driver will feel loose in a JIS screw.
Couldn't resist finding out the difference between JIS and a normal Phiilip's head here. I did wonder why there appeared to be two Phiilip's head screwdrivers in a toolset I bought from Viva Home a while back. Now I know.