Rikuo Motorcycle Co., Ltd., Shinagawa, Tokyo, 1935-62
The story of Rikuo (陸王), and by extension of Harley-Davidson, in Japan is an interesting one. For those wanting some detail, I recommend chapter 4 (the only chapter I've actually read !) of the book by Harry V. Sucher called ' Harley-Davidson, the Milwaukee Miracle', or visit the Vintagent web site for his version or this page at the Motorcycle Classics web site which is actually quite good. The short version of the story is something like this: Both Indian and H-D machines had been sold into Japan prior to the end of WWI and in 1924 an H-D sales office was opened. The Sankyo Pharmaceutical Co., Ltd. was appointed the exclusive importer and sales were fairly steady up until the late 1920's when the Depression started to impact H-D sales globally, along with everyone else of course. In the fall of 1929 the value of the yen collapsed relative to the US dollar making US imports very expensive. Rather than shut down sales and withdraw from the Japanese market, the H-D agent (Alfred Child) negotiated the sale of a complete H-D factory, the intellectual property, the plans, the procedures, the metallurgy, etc. to Sankyo (actually to a subsidiary called Rikuo Internal Combustion Company, or 陸王内燃機) in Japan. This bailed out H-D in the US from a cash flow problem due to the Depression, and allowed cheaper H-D machines to be made domestically in Japan and so preserve the brand name and market presence. Then things got awkward, with the escalation of Japan's war effort on mainland China and escalating tensions between Japan and the US. The plant was basically nationalized in 1937, the bikes being produced were renamed Rikuo and these then continued to be produced in support of Japan's war effort. Of interest is that the former H-D factory was used to produce torpedoes in the 1940/1941 time frame which were used in the attack of Pearl Harbour. H-D didn't advertise their business dealings in Japan which was probably wise at the time.
Production fell of rapidly after the end of WWII and Rikuo Internal Combustion Company went bankrupt in 1949, and then resurfaced as Rikuo Motorcycle Co., Ltd. under the wing of Showa Aircraft company. While the big pre-war flat head twins continued to be made, production of smaller single cylinder models also happened. These were copies of either BMW's or BSA's but it was too little too late. Production ceased completely in 1958 with bikes assembled from spares continuing to be sold till the company was wound up in 1962.
Sucher says in Chapter 4 of his book, that: "in view of the fact that the Shinagawa plant was the very first complete motorcycle manufacturing plant in Japan, it may well be said that Sankyo's effort here was the forerunner of the great Japanese motorcycle industry which today dominates the world markets." I suspect he is probably correct.