Two-up is a traditional Australian gambling game, involving a designated "spinner" throwing two coins or pennies into the air. Players gamble on whether the coins will fall with both heads (obverse) up, both tails (reverse) up, or with one coin a head and one a tail (known as "odds"). It is traditionally played on Anzac Day in pubs and clubs throughout Australia, in part to mark a shared experience with diggers through the ages.
The game is traditionally played with pennies – their weight, size, and surface design make them ideal for the game. Weight and size make them stable on the "kip" and easy to spin in the air. Decimal coins are generally considered to be too small and light and they don't fly so well. The design of pre-1939 pennies had the sovereign's head on the obverse (front) and the reverse was totally covered in writing making the result very easy and quick to see. Pennies can often be observed being used at games on Anzac Day, as they are brought out specifically for this purpose each year.
The exact origins of two-up are obscure, but it seems to have evolved from pitch and toss, a gambling game involving tossing a single coin into the air and wagering on the result. Two-up was popular amongst poorer English and Irish citizens in the 18th century.
The predilection of the convicts for this game was noted as early as 1798 by New South Wales's first judge advocate, as well as the lack of skill involved and the large losses. By the 1850s, the two-coin form was being played on the goldfields of the eastern colonies and it was spread across the country following subsequent goldrushes.
Two-up was played extensively by Australia's soldiers during World War I. Gambling games, to which a blind eye was cast, became a regular part of Anzac Day celebrations for returned soldiers, although two-up was illegal at all other times.
As time passed, increasingly elaborate illegal "two-up schools" grew around Australia, to the consternation of authorities but with the backing of corrupt police. The legendary Thommo's Two-up School, which operated at various locations in Surry Hills, Sydney from the early years of the 20th century until at least 1979, was one of Australia's first major illegal gambling operations.