An elaborate and amusing hoax, purporting to be documentation of a medieval gambling game involving a chequered board similar to a chess board, dice and coins.
See http://www.geocities.com/cartedatrionfi/Fragments/ElTablero.html or http://colynethorfinna.tworavens.org/GamesGuild/articles_tablero.htm for information on the "history" of Tablero.
See also: Tablero da Gucci for a popular An Tirian variation.