I just started watching this anime last night, and I absolutely love it.
It is about the Mutsu clan, and their undefeated unarmed-martial arts, Mutsu Enmei Ryu. It has three story arcs about different members of Mutsu and their influence on historical Japanese swordsmen. It starts off with Mutsu Yakumo, and Miyamoto Musashi. Then, it goes on to Yakumo's son, Mutsu Takato and Yagyu Jubei, and lastly; Mutsu Izumi and Sakamoto Ryoma.
It's a very enjoyable anime, with the fights not being over-done, and the story being amazing. I recommend it highly to any anime fan.