Outstanding king touring a key Japanese port (5)
I believe the answer is:
osaka
'japanese port' is the definition.
(I've seen this before)
'outstanding king touring a key' is the wordplay.
'outstanding' becomes 'os' (accounting abbreviation).
'king' becomes 'K' (chess abbreviation).
'touring' indicates putting letters inside (touring can mean going round).
'key' becomes 'A' (musical key).
'os'+'k'='osk'
'osk' placed around 'a' is 'osak'.
'osak'+'a'='OSAKA'
(Other definitions for osaka that I've seen before include "Japanese city near Kobe" , "Japan's third city" , "Japanese port city" , "Japanese port, on Honshu" , "Kinki's capital" .)