Samurai women were trained to defend themselves and their children. They usually did this when their warrior husbands were busy in battles. This is why samurai women were trained to handle polearms (naginata) and short daggers (tanto). During the Edo period, Japanese women were trained to handle naginata by the age of 18. The short kaiken knife was used by young women to defend their virtue or, if they lost it, to take their own life.