This is an antique Japanese tea cup saucer (chataku) made with pewter and designed with two flags on each side - one is the Japanese flag and one is the Union Jack. This is probably to celebrate the Anglo-Japanese alliance signed in 1906, or perhaps the visit of the crown princes of each country visiting the other (Hirohito in 1921, future Edward VIII in 1922). 

Condition: Excellent - some minor surface wear

Size: 4.75" long x 3" wide