Article snapshot taken from Wikipedia with creative commons attribution-sharealike license.
Give it a read and then ask your questions in the chat.
We can research this topic together.
A kaiken (懐剣, prior to modern orthographic reform kwaiken; also futokoro-gatana) is a dagger formerly carried by men and women of the samurai class in Japan. It was useful for self-defense indoors where the long katana and intermediate wakizashi were inconvenient. Women carried them in the obi for self-defense and rarely for jigai (suicide). A woman received a kaiken as part of her wedding gifts. Many of these daggers had black-lacquered handles and matching scabbards. They could be carried in a pouch of brocade with a drawstring for easy access.
In modern times, kaiken have become part of the traditional Japanese marriage, being one of the items carried by a bride for good luck.
