A man from Golcar, West Yorkshire was recorded in 1974 for the Survey of English Dialects discussing knurr and spell being played around the turn of the twentieth century.
[7] In Yorkshire it is played with a levered wooden trap known as a spell, by means of which the knurr, about the size of a walnut, is thrown into the air.
[2] Originally the ball was thrown into the air by striking a lever upon which it rested in the spell or trap, but in the later development of the game a spell or trap furnished with a spring was introduced, thus ensuring regularity in the height to which the knurr is tossed, somewhat after the manner of the shooter's clay pigeon.
By means of a thumb screw, the player can adjust the spring of the spell or trap according to the velocity of release desired for the ball.
[2][6] On a large moor, where the game is generally played, the ground is marked out with wooden pins driven in every 20 yards (18 m).