The only Japanese square taper cranks I have come across that used ISO tapers have been branded Sugino. (I'm aware that Suntour cranks were at least sometimes manufactured by Sugino. But I don't recall ever having encountered ISO taper Suntour cranks.)

Sugino were ahead of their time in the proliferating-standards game when they introduced an incompatible proprietary square taper for their "Maxy" cranks.