The purpose of the article is to consider one of the most fruitful periods of Russian-Japanese cooperation, during which the parties, having survived the vicissitudes of the war, took the path of political, economic and cultural cooperation. The apotheosis of this cooperation was the conclusion in 1916 of a militarypolitical agreement that formed, in fact, a military-political Union of the two countries. However, the subsequent February and then October revolutions in Russia completely negated the successes achieved after the Russian Japanese war.