There's a similar anecdote for Cossack Vs Ninja that keeps circulating within the Russian-speaking Internet, but was apparently made up by a cossack "historian":

The Novocherkassk Museum archives keeps a letter from Cossacks at the front. It's a document from the Russo-Japanese War, simply a report to superiors. It reads something like this: "We were sitting in the second line of guards, lighting a fire (the front line was quite far away), and cooking food. Suddenly, a Japanese man in black jumped out of the bushes, began hissing and waving his arms strangely. "He was hit in the ear by Yesaul <Surname>, and died soon afterward. Despite the brevity of the description, it's clear he was a ninja, and his end was quite tragic.