Japanese drama about a boatman (4)
I believe the answer is:
noah
'boatman' is the definition.
(I have seen 'Early boatman ' mean 'noah' so perhaps 'boatman' could also mean 'noah')
'japanese drama about a' is the wordplay.
'japanese drama' becomes 'noh' (type of drama in Japan).
'about' indicates putting letters inside.
'noh' going around 'a' is 'NOAH'.
(Other definitions for noah that I've seen before include "Oh, an ark man" , "Hebrew patriarch who survived the Flood" , "Early boatman" , "Legendary Biblical boat-builder" , "Floater" .)