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|Founder||Aizu Hyūga-no-Kami Iko (c.1452–1538)|
|Period founded||Sengoku period (mid-15th century–mid-17th century)|
|Yagyū Shinkage-ryū • Kashima Shinden Jikishinkage-ryū|
Kage-ryū (陰流) is a traditional school (koryū) of swordsmanship (kenjutsu) founded by Aizu Hyūga-no-Kami Iko (c.1452–1538) in c.1490. This school is also sometimes called Aizu Kage-ryū after the name of its founder. The founder was also known as Aizu Ikōsai Hisatada, and his surname is sometimes written as "Aisu" instead of "Aizu."
Aizu had two primary students, his son Aizu Koshichiro, and Kamiizumi Hidetsugu. Kamiizumi Hidetsugu would go on to teach Kage-ryū to his son Kamiizumi Ise-no-Kami Nobutsuna, a famous swordsman and founder of Shinkage-ryū (新陰流) (which would be renamed Yagyū Shinkage-ryū by Nobutsuna's equally famous student Yagyū Sekishūsai Muneyoshi.
Today, the Kage-ryū of Aizu Hyūga-no-Kami Iko exists only through its influence of later schools of swordsmanship, such as Yagyū Shinkage-ryū and Kashima Shinden Jikishinkage-ryū, and the many schools that they in turn influenced.