Tsukuba (tsŏŏkōō´bä), city (1990 pop. 143,396) Ibaraki prefecture, central Honshu, E central Japan, 31 mi (50 km) S of Mito. The city's products include peanuts, mushrooms, tea, processed foods, sake, and housewares. It is the site of Tsukuba Science City, a research and technology center. The government began planning the science city in 1963 as a center dedicated to scientific research and as part of a strategy to decentralize Tokyo. It served as the site of Japan's science exposition in 1985. The city houses 46 national research facilities, including the National Laboratory for High Energy Physics. The Univ. of Tsukuba is located there.