This round is Japanese, for the 5cm Boat Gun (47mm Hotchkiss Revolver Cannon) (47x131R). The case was made by the Elswick Ordnance Company in England, on contract for Japan, while the projectile is of Japanese manufacture (Kure Naval Arsenal). The rotating band is the standard Hotchkiss design of the period. Later projectiles had a much narrower copper rotating band, and will be found with cases of Japanese manufacture. The 5cm Boat Gun stayed in service with the Japanese Navy until the end of WWII. I’ve seen a case dated 5th month 20th year Showa (May 1945).
Examples of these can be found with both brass and copper multi-groove rotating bands.