Lady Kai (甲斐姫) ("hime" means lady, princess, woman of noble family), speculated to have been born in 1572, was a Japanese female warrior, onna-musha from the Sengoku Period. She was the daughter of and granddaughter of Akai Teruko, retainers of the Later Hōjō clan in the Kantō region. She is known as the heroic woman who helped her father's resistance at Oshi Castle against Toyotomi Hideyoshi's army during the siege of Odawara. After the war, she became one of the wives of Hideyoshi. She was known for her bravery and beauty. According to the chronicle of Narita clan, she was praised as "The most beautiful woman in east Japan".（東国無双の美人）