Rice wine mostly found in outer parts of Okayama, city in Japan (5)
I believe the answer is:
osaka
'city in japan' is the definition.
(I've seen this in another clue)
'rice wine mostly found in outer parts of okayama' is the wordplay.
'rice wine' becomes 'saki' (I've seen this before).
'mostly' means to remove the last letter (most but not all of the word).
'found in' is an insertion indicator.
'outer parts of' suggests removing the centre.
'okayama' with its middle removed is 'oa'.
'saki' with its last letter taken off is 'sak'.
'sak' put inside 'oa' is 'OSAKA'.
(Other definitions for osaka that I've seen before include "Third most populous Japanese city" , "in east Asia" , "Port city on Honshu, Japan" , "Asian" , "Third largest city in Japan" .)