Riken is a national scientific research institute in Japan. Founded in 1917, it now has about 3,000 scientists on seven campuses across Japan, including the main site at Wakō, Saitama Prefecture, on the outskirts of Tokyo. Riken is a Designated National Research and Development Institute, and was formerly an Independent Administrative Institution.

Wakō is a city located in Saitama Prefecture, Japan. As of 1 January 2021, the city had an estimated population of 84,161 in 42,434 households and a population density of 7600 persons per km2. The total area of the city is 11.04 square kilometres (4.26 sq mi).