Ya is the term for an arrow (as fired from a bow). Ya shafts were traditionally made of bamboo, with either eagle or hawk feathers.
Historic Ya (OOC)
Every ya has a gender (male ya are called haya; female ya, otoya); being made from feathers from alternate sides of the bird, the haya spins clockwise upon release while the otoya spins counter-clockwise. Kyūdō archers usually shoot two ya per round, with the haya being shot first. It is often claimed that the alternate spinning direction of the arrows would prevent two consecutive identically shot arrows from flying identically and thus colliding.
Retrieved from http://en.wikipedia.org/wiki/Kyūdō