Japanese Cryptology From The 1500s To Meiji - Discrepancies

Discrepancies

Interestingly, Kahn writes that Kowalefsky had been in Japan from about 1920, when he was supposedly helping improve Japanese codes, and was still there in 1925 to teach at a new Navy code school. That is, Kahn has Kowalefsky working for the Navy, not the Army. Japanese sources make it clear that both Army and Navy officers attended Kowalefsky's three-month course, so some confusion is possible. However, Yardley wrote, correctly, that Kowalefsky worked for the Army but was wrong about the year since he claimed that the Polish expert had arrived in 1920. Yardley's error might explain why Kahn had Kowalefsky arriving in the wrong year but nothing in Yardley suggests that Kowalefsky ever worked for the Navy.

Although they do mention Kowalefsky (if not by name) neither Kahn nor Yardley mentions anything about Japanese cryptologists training in Poland or even Kowalefsky returning home. Thus, probably the most widely read English books on cryptological history are possibly missing a large and important part of the development of professional cryptology in Japan – if the Japanese sources are correct. If the Japanese sources for this history can be confirmed, it would be an important addition to the understanding of Japanese cryptology leading up to World War II. Polish cryptanalysts were very good and if they tutored the Japanese for almost fifteen years, it makes the Japanese failure to break most of the Allied codes during the war much more interesting.