150 Baht - Rama IX 60th Birthday - King Rama IX

Issued to mark the 60th birthday of Bhumibol Adulyadej, who by 1987 had already reigned for over four decades — making him one of the longest-serving monarchs alive at the time. In Thai tradition, a 60th birthday completes five full cycles of the twelve-year lunar calendar, a milestone considered especially auspicious and typically marked with significant ceremony.

The Royal Thai Mint struck commemorative 150 Baht pieces in this period across several occasions, and Y#197 sits within a crowded commemorative program from the mid-1980s that has kept secondary market premiums modest for most issues in the series.