Reduce the list, select first 2 letters of the city:
Listing cities (177 place(s)). Select the City to see the postcode(s):
Listing cities (177 place(s)). Select the City to see the postcode(s):
Position: Postcodes > Japan > Ibarakiken > O.... >
Postcode finder: Japan, List of the cities starting with O. Japan Ibarakiken Postcodes (Desktop version).