Bhutan switched to the metric system of measures in 1957. But only nine years later Bhutan minted his own new coins, called the "naya paisa". They were issued in 1966 from a Copper-Nickel with a par value of 25 and 50 naya paisas, 1 and 3 rupees.

The first Proof set of coins of Bhutan was minted in 1966 (6,000 copies).in the Royal Mint.

This serie of coins is devoted to 40th Anniversary - Accession of Jigme Wangchuk.

The obverse shows Jigme Wangchuk.

On the reverse there is the emblem of Bhutan.