Rummy came First

The history of Gin Rummy is closely tied up, naturally enough, with the history of Rummy in general, so we'd better start by disentangling one from the other. Rummy itself not so much a specific game as a large family of games based on a particular way of playing with cards. It's a method generally known as 'draw and discard', because at each turn you draw one or more cards from a stockpile and throw out an unwanted card in exchange. Your aim in doing this is to form your hand into sets of matching cards, or melds.

A meld is either:

• (a) three or four cards of the same rank, such as Aces, Kings, Sixes, or whatever, or
• (b) three or more cards in suit and sequence, such as Spades A-2-3-(etc.) or Hearts A-K-Q-J-(etc).

Any game based on draw-and-discard and making melds is some sort of Rummy game by definition. (Unless it also involves trumps and tricks, in which case it's a form of Pinochle or Bezique.) Given this same underlying procedure, Rummies fall into several groups according to their respective aims and rewards.

In the original and oldest version, which Gin closely resembles, the aim is to be the first to get rid of all your cards by laying them face up on the table in matched sets called 'spreads', or, later, 'melds'. You then get a score based on the penalty value of all the cards left unmatched in your opponents' hands - their 'deadwood', as it's called. In later branches of the family, such as Michigan, you don't just score for other players' deadwood but also get a score based on the value of all the cards you have melded yourself.