Its my understanding that the yari is a straight blade weapon with several cutting edges, whereas the naginata is a single edged sword blade on the end of a shaft. The translation for naginata is ‘long sword’ I was told. The yari could be used to slash, but was primarily a thrusting weapon. Its shaft was round in cross section. The naginata, on the other hand, had an oval shaft cross section, and was first used to stop cavalry charges by slashing at the horses’ legs. The oval shape easily allows the user to orient the single blade properly. During the Tokugawa peace, samurai found it cumbersome to carry, opting for the swords instead. The weapon was left at home, where women were to use it to defend the household and their honor. This is how it became primarily a woman’s art.

Perhaps to some these are minor distinctions, but I do know that I would be at a loss if I tried to use a yari effectively. On the other hand, I would be very comfortable using the sweeping slashing strokes that are the signature of the naginata techniques.