Universal History Annotation << Back On the Uranium Project of Japan in 1940-s Gorobets B.S. The history of Japanese atomic project carried out during the Second World War is unknown to almost all the Russian scientific community, including nuclear physicists. This report presents generalization of different foreign and Russian publications on the problem. The quintessence of it is as follows. The leading Japan physicists were Т. Hagivara, I. Nisina, R. Sagane, Ts. Asada, B. Arakatsu, М. Киkuchi, who knew well of the key achievements of nuclear physics abroad. They knew that, in principle, it was possible to make atomic bomb with the charge of uranium-235. In spring of 1940, Sagane was charged by general T. Yasuda to make the basic review of nuclear problem. In autumn, Sagane rendered an account with his conclusion that it was, in principle, possible to make atomic bomb in Japan. In the end of 1942, Nisina began to work out «Ni-Project» in the Institute of Physical and Chemical researches (RIKEN), in Tokio. In may 1943 Nisina gave an account in which he affirmed that making an atomic bomb would require 1 kg of uranium-235. this one being equivalent of 18 thousand t. TNT. The main problem was to manage to separate uranium isotopes-235 and 238. A few months before the end of the war, the Navy commandment charged B. Arakatsu to head so-called «F-Project». These researches were carried out in Kioto University. But the scales of both projects were scanty, compared to the giant goal. Not more than 15 specialists were engaged in «Ni-Project», and even less than that in «F-project». Nevertheless, the RIKEN group managed to mine 150 t of uranium ore in Japan, Korea and Malaya and then to extract out of it as much as 300 kg U3O8. It corresponded to 1,8 kg of uranium-235. The Japanese tried to build a centrifuge machine in order to separate isotopes-235 and 238 in form of uranium hexafluoride gas. But they failed. The summary financing of Ni-project by the Army was 2 mln yen, and financing of F-project by the Navy was 0.6 mln yen. It was equivalent of 650 thousand dollars, i.e. 3 thousand times less than costs of Manhatten project (USA and England). In that way, Japan had no time and no adequate resources to build atomic industry and atomic bomb. After the atomic bombardment of Hiroshima and Nagasaki, 6 and 9 of Аugust 1945, Japan was informed that the third atomic bomb would be thrown down, possibly upon Tokio, if the Empire not surrender. The capitulation of Japan was declared 2 September 1945. Кeywords: Japanese аtomic project, Japanese uranium ores, uranium-235, Iosio Nisina, Bunsaku Arakatsu, capitulation of Japan. Contacts: Email: bgorobets@rambler.ru Pp. 40-47.