Also known as: 懐刀
Translating as "chest sword", a small Dagger held in a small, decorative brocade-fabric purse tucked into the collar of a woman's wedding Kimono. Similar to a kaiken. (Wikipedia
Sometimes, they can tucked in the Obi instead. The purse that holds the futokorogatana is usually tied with Flower Knot.
Usually comes in a set with a Hakoseko and a Folding Fan.