Japanese ruler (6)
'japanese ruler' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for shogun that I've seen before include "Feudal Japanese leader" , "Hereditary army commander in feudal Japan" , "Old Japanese hereditary army commander" , "Hereditary commander-in-chief in feudal Japan" , "So hung about with old Japanese army commander" .)
(Other definitions for mikado that I've seen before include "Japanese emperor as in G & S operetta" , "Musical emperor of Japan" , "Gilbert and Sullivan's emperor" , "Japanese 2" , "Japanese ruler" .)