was a Japanese noble lady and politician from a prominent Japanese samurai family of the Azuchi–Momoyama and Edo periods. Born Saitō Fuku (斉藤福), she was a daughter of Saitō Toshimitsu (who was a retainer of Akechi Mitsuhide). She was the wet nurse of the third Tokugawa shōgun Iemitsu. Lady Kasuga was one of the best politicians in the Edo period. She stood in front of negotiations with the Imperial Court and contributed to the stabilization of the Tokugawa Shogunate.
Kasuga was one of the most powerful figures in the Ōoku (the quarters in Edo Castle where the women related to the Shogun family resided) . She is counted alongside Matsudaira Nobutsuna and Yagyu Muneyori as one of the Three Tripod Legs, who supported and propped up Iemitsu.
Early career
Saitō Fuku was from the Saitō clan, a prominent samurai house that had served for generations as deputy military governors of Mino province. She was born in Kuroi Castle of Tanba province (comprising modern-day Hyogo and Kyoto Prefectures), which is where her father's territory was then located. Tanba Province was under the overlordship of Akechi Mitsuhide, and her father, Saitō Toshimitsu, as his retainer, was enfeoffed on that territory by Mitsuhide. Her mother's father was Inaba Yoshimichi.
Fuku's father joined Akechi Mitsuhide's rebellion to kill Oda Nobunaga during the Honnō-ji Incident. After Nobunaga was assassinated by Mitsuhide, the Saito and Akechi clan were defeated by Hashiba Hideyoshi during the Battle of Yamazaki. Then Fuku's father, Toshimitsu, retired to his castle; later he was caught in Omi province, near Sakamoto Castle, and was executed. It is thought that his various brothers, having become defeated and hunted warriors, wandered from place to place trying to escape the enemy. One theory holds that after the Battle of Yamazaki, she had relied on Chosokabe Motochika, her uncle, for help, and had spent some time at Oko Castle in Tosa province
Because Fuku was a woman, she was spared execution and was raised by her maternal relative, aristocrat Sanjonishi Kinkuni. After being adopted, she received the highest education as an aristocrat of the privileged class. She learned the arts considered essential for the nobles of the Imperial court, including the arts of calligraphy, waka poetry and mixing incense.
She was later adopted by her uncle, Inaba Shigemichi, and became the wife of Inaba Masanari, a retainer of Kobayakawa Hidekai During the marriage she had three sons, including Inaba Masakatsu, and an adopted son, Hotta Masatoshi.
Joining the Tokugawa clan
In 1600, during the Sekigahara campaign, Fuku's husband, Inaba Masanari, served Kobayakawa Hideaki in the Western army led by Ishida Mitsunari. Due to the tensions Hideaki had with Mitsunari and the progression of the war being favorable to the Eastern army led by Tokugawa Ieyasu, it is said that Fuku and Masanari achieved the great feat of making Hideaki change sides and join the Eastern army. After Hideaki joined Ieyasu, Mitsunari's army was defeated, as a result of which the Fuku family obtained a large amount of spoils of war.
After that, she took the step of divorcing her husband Masanari to become a wet nurse in the shogunal family and, in 1604, was formally appointed as the wet nurse of Takechiyo (the childhood name of Tokugawa Iemitsu), the legitimate son and heir of the second shogun, Tokugawa Hidetada. She was recommended to Tokugawa Ieyasu by Itakura Katsushige for the position of wet nurse for Tokugawa Iemitsu, but there is a theory that Ieyasu chose her on his own. They say that Fuku's excellent pedigree, refined and aristocratic education and the military exploits of her ex-husband Masanari were all positive factors in her selection as a wet nurse. She was chosen for the job as a payment because she helped persuade Kobayakawa Hideaki to join the Eastern Army in the Battle of Sekigahara.
Shogun's Wet-nurse
Lady Kasuga joined the Tokugawa clan as a wet nurse to Tokugawa Iemitsu, heir of Tokugawa Hidetada. During her lifetime she accumulated high political prestige, being responsible for numerous negotiations with the Imperial court, maintenance in the shogunate cabinet, hiring officials and stabilizing the Ooku system.