Japanese physicist who, with T. Nakano, developed the concept of "strangeness" to refer to properties of some subatomic particles. Strangeness is one of the so-called "quantum numbers" that can be used to describe how these particles behave. Other examples of quantum numbers are the baryon number, hyperon number, and electrical charge. Together, these quantum numbers give a great deal of predictive and interpretive power for understanding and classifying these particles.