This sent me down a rabbit hole of “Why do japanese dice use a big red circle for a one” and came back more confused than before. Chinese dice have ones and fours painted? But nobody actually seems to know how far back this goes, or why except for an apocryphal story about the origins of red painted 4-pips in china.
If anybody has any insight to this, I’d be happy to hear it because the lack of information is baffling.