In and In, also spelled Inn and Inn, was an English dice gambling game. The earliest descriptions of this game are from the 17th century, but by the 18th, Oliver Goldsmith described it as a game which was “now exploded, [that] employed our sharping ancestors”.A[p. 57]
The name is somewhat lewd as it was also used to refer to sexual intercourse (see A Dictionary of Sexual Language and Imagery in Shakespearean and Stuart Literature (p. 707) for many quotes and puns upon the name) — “in and out” is a more modern version of this usage. CottonC[p. 164] describes the game as being commonly played in inns (“ordinaries”).
The game is played by two or three people and uses four dice. The rules of the game are not obvious from Cotton’s text, but my reconstruction is as follows.
Each round, a player rolls all four dice once. A pair or double of the same number is called an in, and two pairs is called in and in. If a player rolls an in, they pay a stake to keep playing. If they roll in and in, they win the whole pot that has accumulated so far. If they fail to roll any pairs, then they are out: the other player or players win the pot.
The probability of throwing at least a pair on four dice is 13⁄18 ≈ 72.22%. However, the probability of throwing two pairs is only 2⁄27 ≈ 7.41%.
Cotton indicates that the game might be played for a specified sum or battail (old spelling of ‘battle’), and the game would not be over until all the money of the battail was paid out. To play like this, each player could contribute an equal amount of money to the battail, and afterwards any stakes paid would come out of the battail but winnings would go to each player.
Goldsmith, Oliver (). The Life of Richard Nash, Eſq; Late Master of the Ceremonies at Bath (2nd edition). London.
Williams, Gordon (). A Dictionary of Sexual Language and Imagery in Shakespearean and Stuart Literature volume 2: ‘G–P’. The Athlone Press: London and Atlantic Highlands, NJ. ISBN: 0-485-11393-7.