Yoichiro Nambu
In 1950, while at Osaka University, Nishijima was hired by Yoichiro Nambu to work on the theory of strong interactions and of strange particles (then called V particles). While studying the decay of these particles, Nishijima developed, with , and independently of Murray Gell-Mann, a formula that would relate the quantum numbers of these particles, the Gell-Mann–Nishijima formula (or sometimes the "NNG formula", for Nishijima, Nakano, and Gell-Mann).