This manga is based on the popular novel, Musashi written by Eiji Yoshikawa.
Musashi Miyamoto is a well known samurai. His legendary fight with Sakaki Kojiro lies in every mind. But, who is Musashi Miyamoto actually? Where did he come from?
He was born with the name Shinmen Takezo. Being a dependable boy, he grew up with a strong heart. Later, he became a cold heartless fighter. He was so poor. You know, at the time when wars happen, the landlord asked young boy to join the army? Takezo went there with his best friend. They were caught in the middle of Sekigahara war. They pretended to be dead to survive. They realized how small and weak they are. From that moment, Takezo started to grow a mission inside: to be a great samurai. He started with a stick, first. But, he defeated many people with that. It shaped his skills.
http://strays.vnmanga.com/ has released the scans.