The pre-decimal sixpence (6d) was a unit of currency equalling one fortieth of a pound sterling, or six pence sterling. It was used in the United Kingdom, and earlier in Great Britain and England.
The denomination had undergone several earlier changes: the King George III sixpence (1816 - 1820), King George IV first issue (1821 only), King George IV second issue (1824 - 1826), the first "wreath" type (1831 - 1887), a brief withdrawn version featuring the Coat of Arms, a second "wreath" type (1887 - 1910), the English Lion on a crown (1911 - 1927), and then the Oak Sprigs design (1927 - 1936).
This design, featuring the crowned cypher (monogram) of the monarch, was introduced for King George VI at the beginning of his reign in 1937. It was replaced with a new style of monogram in 1949, after the title Emperor of India was dropped from his legend due to the Independence of India.
The composition of the coins was initially 0.500 silver with 0.0452 oz ASW (ounce of Absolute Silver Weight), which was debased to copper-nickel after 1946. Sixpences continued to be legal tender for a while after the currency became decimal in 1971, with a value of 2 1⁄2 new pence, until they were demonetised on 30th June 1980.
Within a beaded border, the obverse of the coin shows the bare (uncrowned) head of King George VI facing left.
Below the neck truncation in small letters, the artist's initials HP (for [Thomas] Humphrey Paget).
Around, part of the the monarch's legend: GEORGIVS VI D : G : BR : OMN : REX, which is an abbreviation from GEORGIVS VI DEI GRATIA BRITANNIARUM OMNIUM REX; translated from Latin, it means "George the Sixth, by the Grace of God, King of all the Britains". The rest of the legend is on the reverse.
Within a beaded border, the reverse of the coin shows the crowned royal cypher GRI, for GEORGIVS REX IMPERATOR - "George King and Emperor" - dividing the date: [year].
Below the monogram in small letters, the designer's initials K · G (for [George] Kruger Gray).
Around above, interrupted by the cross on top of the crown, the continuation of the monarch's legend: FID · DEF · · IND · IMP - abbreviated from FIDEI DEFENSOR INDIAE IMPERATOR: "Defender of the Faith, Emperor of India".
Around below, the denomination as one word: SIXPENCE.