Japanese city with large area occupied by a king (5)
I believe the answer is:
osaka
'japanese city' is the definition.
(I've seen this before)
'large area occupied by a king' is the wordplay.
'large' becomes 'os'.
'area' becomes 'a' (maths abbreviation).
'occupied by' is an insertion indicator.
'king' becomes 'k'.
'os'+'a'='osa'
'a'+'k'='ak'
'osa' placed around 'ak' is 'OSAKA'.
'with' is the link.
(Other definitions for osaka that I've seen before include "Japan's third city" , "Japanese port city" , "in east Asia" , "Port city of southern Honshu" , "Asian" .)