Originally, the naginata was used by warrior monks who would defend their
shintoist temples from invaders. This weapon fell out of favor after the
14th century, when the temples were no longer a target. At any rate,
the samurai did sometimes use the naginata while fighting at close
quarters on horseback.
The naginata was made from a short, curved blade, like that of the
wakizashi, but instead of being attached to a normal sword hilt, it
was attached to a long staff. The naginata staff could be anywhere from
38" to 4 feet long. This made the weapon extremely useful in close
quarters, where it's wielder could keep sword-carrying attackers out of
range. The age in which the naginata was most commonly used is the age
in which the samurai were mostly archers, which meant that sword vs.
naginata battles rarely took place.
Some schools of martial arts still use the naginata today, however, the
modern naginata more resembles the european Halberd, with the blade
resembling a scimitar moreso than a wakizashi.