(from ebookjapan):

One day, a Japanese boy who wanted to become a policeman came to a border town deep in Brazil. In fact, this boy was dispatched by "JJ," an extra-judicial organization that rescues suffering Japanese abroad.

The ten men secretly dispatched by the JJ agency do not know the names or faces of their comrades, and their only clue is that they have a common marker!

Can be considered the mangaka's second attempt at "Musashi"