AD&D 1.5

purely conjecture here, since I haven't read any of the books, but apparently AD&D "1.5" comprises the releases of Unearthed Arcana, Oriental Adventures, the Dungeoneer's Survival Guide, and the Wilderness Survival Guide. As big of a weaboo as I used to be, I might enjoy playing a fantasy Japan themed setting with the new rules bloat from non-weapon proficiencies and such.  Though I imagine that in almost 40 years, a much better RPG system to emulate feudal Japan must have come out.