Women sometimes carried a small tantō called a kaiken[6] in their obi primarily for self-defense. Tantō were sometimes worn as the shōtō in place of a wakizashi in a daishō,[7][8] especially on the battlefield. Before the advent of the wakizashi/tantō combination, it was common for a samurai to carry a tachi and a tantō as opposed to a katana and a wakizashi.[7]