Diplomatic relations with Japan take effect.

What happened

Japan had ruled the islands from 1914 to 1945, and it became one of the FSM’s main partners: by 2017 its grant aid had reached ¥23.3 billion. Sources disagree on the start date. The FSM newsletter says 16 December 1988, Japan’s foreign ministry says December 1988, and Wikipedia gives 5 August 1988.