Thailand, but without knowing the size it would take forever to find it in the SCWC. The King has been using youthful busts for more than 50 years!
This coin was struck in tin (greyish metal) or aluminum-brass (yellow metal). It is difficult to tell from the scan which color the coin has. The person depicted on the coin is the reigning king Rama IX or Bhumiphol Aduljadeh. He became king in 1946 after the unexpected death of his brother Rama VIII Ananda Mahidol.