seimei is a Go port of a tool (namedivider-python) created in python to split Japanese first and last names.
For implementation details, please check (namedivider-python) from which porting.
go install github.com/glassmonkey/seimei/cmd/seimei@latest
$ seimei -h
-name string
separate full name(ex. 田中太郎)
-parse string
separate characters (default " ")
$ seimei -name 竈門炭治郎
竈門 炭治郎
$ seimei -name 竈門禰豆子 -parse @
竈門@禰豆子
glassmonkey(@glassmonekey)