Picaria (meaning "little stone") is a two-player abstract game from the Tewa tribe of the Pueblo people of the North American Southwest. Most likely it was derived from games introduced to the introduced to the natives by the Spanish in the 17th Century. It is similar to tic-tac-toe, but more related to Three Men's Morris, Achi, Tant Fant, and others because the pegs can be moved after they are placed on the board. An exact twin can be found in Scandinavia where it is called "luffarshack" and in Asia as part of the Ko-no tradition. Picaria in particular was first described in academic circles by the American game historian Stewart Culin in 1907. The game was analyzed by Larsson and Rocha at Dalhousie University, Halifax, Canada.