It appeared under the cold war as a strategic bomber which can oppose B-52 (U.S.A.). The greatest feature is having adopted the ncy in order to earn a cruising range. Moreover, the design which equips with a double reversal propeller and uses the output of the engine of a large horsepower efficiently is also taken in. The cruising range which, as a result, amounts to no less than 15,000km is realized. A reconnaissance plane type is also made besides a bomber type, reconnaissance activities are carried out in the Sea of Japan, and a photograph may be taken by the Self-Defense Forces. 300 or more sets are manufactured in all.