Lady Kai (甲斐姫?) ("hime" means lady, princess, woman of noble family), speculated to have been born in 1572, was the daughter of Narita Ujinaga, retainer of the Late Hōjō clan in the Kantō region. She is known as the legendary woman who helped her father's resistance at Oshi Castle against Toyotomi Hideyoshi's army during the Siege of Odawara. Though known for her bravery and beauty, modern historians are unsure if she actually performed the deeds in the tales surrounding her and it is highly likely that many of her feats stem from contemporary historical novels or folklore from the Edo period.
In June 1590, Ishida Mitsunari led a 20,000-man army to take Oshi Castle. Owing to lack of foresight and planning, his army was devastated by a water attack. Kai was said to have volunteered to rout the remaining soldiers, donning armor and riding on horseback with 200 men. When Ishida was reinforced by Sanada Masayuki, Sanada Nobushige and Asano Nagamasa, she was said to have slain the Sanada retainer, Miyage Takashige. When Odawara Castle surrendered, her father also chose to do the same with the hope of ending warfare.
She and her father were put under Gamō Ujisato's care for a time. Sometime when her father was away, an internal rebellion was caused by Hamada Shugen and his younger brother (historical records suggest that the revolt was actually started by Ujinaga's brothers). During this time, Kai's mother-in-law was killed. As soon as she heard about the incident, Kai brandished a sword and sought to end the rebels. She slew the instigator and two followers, effectively repressing the bloodshed. Hideyoshi heard of her bravery.As a result, her father became one of Hideyoshi's trusted generals. He was rewarded with Karasuyama Castle and 20,000 koku.
In popular culture
Kaihime appears in Koei's video game Samurai Warriors 3 and Samurai Warriors 4, where her weapon is a sword-whip, and in the video game Takeda 3, as a general named Narita Kaihime. She also appears as a character in Irem's trading card video game Sengoku Efuda-yugi: Hotogisu Ran. She is a playable character in Pokémon Conquest (Pokémon + Nobunaga's Ambition in Japan), with her partner Pokémon being Darumaka and Darmanitan. Professional wrestler Hiroyo Matsumoto wrestled as Kaihime for the Dramatic Dream Team promotion on February 10, 2013.
- Himegimi-tachi no Dai Sengoku Emaki (姫君たちの大戦国絵巻); ISBN 978-4-404-03705-3