Aruga Nagao

was a Japanese legal expert during the Meiji period. In addition to law, he also studied sociology at Tokyo Imperial University. During the Sino-Japanese war, he advised Field-Marshal Ōyama Iwao on issues of international law. In 1913 he accepted the invitation by Yuan Shikai, to prepare a draft constitution for the new Chinese republic, together with . Ariga doubted that China was ready to implement a liberal democracy and recommended a balance between monarchy and republic.

Ariga also worked as a translator.

Works (partial list)

La Chine Et La Grande Guerre Europeenne Au Point de Vue Du Droit International D'Apres Les Documents Officiels Du Gouvernement Chinois La guerre sino-japonaise au point de vue du droit international La Guerre Russo-Japoinaise 1904-1905 Kinji gaikōshi (History of foreign relations in modern times) (1898)