The Overhand Throw

After choosing the proper grip, cock the throwing arm just
behind the ear. Shifting the weight as explained in the
description of the throwing stance, cast the throwing arm
forward at the target, releasing the throwing knife just
before the end of the stroke. Follow through and recover.
Photos 2.19 and 2.20 show a Ninja using a blade grip in the
overhand throw.
The Underhand Throw
After selecting the proper grip, cock the throwing arm
back behind the hip. Propel the throwing arm forward,
releasing the throwing knife at the proper moment, just
before the end of the stroke. Follow through and recover.
Photos 2.21 and 2.22 show a Ninja using a palm grip in the
underhand throw. In this particular type of throw, the knife
is thrown straight into the target, usually at close range
(approximately ten feet or less). An interesting variation of
this throw reverses the motion, beginning with the knife in
front of the thrower. Ninja use this technique to throw
knives at pursuers while running.