Senbon Matsubara: Kawa to Ikiru Shounen-tachi

せんぼんまつばら 川と生きる少年たち

The story

After suffering severe floods in 1753, the people of Senbon Matsubara in Shizuoka cooperate on flood prevention around the Kiso, Nagara, and Yuhi rivers. The people of Satsuma (Kumamoto Prefecture) endure great hardships after being forced to undertake the work by the central government, a subtle indication of the bad feeling that would foment into open rebellion the following century. (Source: AnimeVice)