The Book of Games

In 1238, the medieval Spanish ruler Alfonso X of Castile published a tome called Libro de los Juegos,  or The Book of Games. It consisted of 97 parchment pages, many with beautiful color illustrations, and contains the earliest descriptions of games such as chess, dice, and backgammon.

Alfonso went on to classify games into three categories: games that are played on horseback, games played dismounted (such as fencing and wrestling), and games played seated. He divided this third category even further into games that rely on the brain, games of chance, and games that rely on both.

In making these distinctions, Alfonso is the unofficial founder of a field of science known as ludology—the study of games.

These games can be modeled as mathematical entities that lend themselves to computational study. This is based on the idea that games are composed of units of information called ludemes, such as a throw of the dice or the distinctively skewed shape of a knight's move in chess.

Ludemes are equivalent to genes in living things or memes as elements of cultural inheritance. They can be transmitted from one game to another, or they may die, never to be seen again. But a key is that they can be combined into bigger edifices that form games themselves.