This type of pottery combines the 400 year old Japanese process of Raku pottery with the Southwest art of decorating pots with horsehair. The individual pot is removed from a red hot kiln at 1900 degrees and placed top first in a reduction pit of sawdust. When the pot cools some, individual strands of horsehair are laid on the surface of the piece. The black lines you see are carbon trails left from the burning horsehair.
Not to be used as functional, food safe pottery.
Will not hold water.