Asu no Yoichi [TV]
Karasuma Yoichi is a swordsman living a solitary life in the mountains with his father. One day, at the age of 17, his father sends him to the city, into the care of the Ikaruga family.
Now, the Samurai throwback must not only adjust to living in a bustling city, modern society, and a normal high school, but he must also adjust to living with the four Ikaruga sisters, Ibuki, Ayame, Chihaya, and Kagome!
*Thanks to Cranston for the description