Samurai Ragazzi

Samurai Ragazzi - Sengoku Shounen Seihou Kenbunroku (サムライ・ラガッツィ　戦国少年西方見聞録 Samurai Ragattsi Sengoku Shōnen Seihō Kenmonroku) is a Japanese manga series written and illustrated by Tatsuya Kaneda.

Plot
Nobunaga was just taken out of power and there are signs of civil unrest even in the far reaches of Kyuushuu. A small precinct of Kyuushuu is ruled by the Harima family and headed by the 15 year old Harunobu who, despite everyone's hopes, has no interest in war nor being a lord. Instead, he spends his time surveying the land to make maps or record plant and animal life. Harunobu's dream is to create an encyclopedia that contains all the information in the world. So when the opportunity to travel the world and eventually end in Rome appears, Harunobu leaves the land in capable hands and sets sail on his journey that he has dreamed of his entire life.