I’m thinking about writing a variant of Tilly’s Very Bad Day for the Japanese “Age of Warring States” (Sengoku Jidai). Samurai, mounted Samurai with bow or lance, Ashigaru, firearms, that kind of thing.
What follows is a set of design notes examining how Tilly’s Very Bad Day (TVBD) maps onto large battles of Sengoku-period Japan.
To be honest I don’t think Tilly’s Very Bad Day needs extensive mechanical change and the rule align closely with Sengoku warfare — provided they are framed and applied with the right assumptions.