This prize is given to a Japanese operator algebraist (in a wide sense) of age 40 or less every four years. It started in 2000.

*The prize of 2000 was given to Yasuyuki Kawahigashi.*

The first Operator Algebra Prize of Japan is awarded to YASUYUKI KAWAHIGASHI of the University of Tokyo. Kawahigashi was chosen for his outstanding contributions to the theory of automorphism groups of injective von Neumann algebras and the subfactor theory and thus to the advancement of operator algebra theory. He will receive a cash award of 300,000 Japanese yen (about US$2,700), a certificate, and a medal.

The Operator Algebra Prize was established in April 1999 by senior Japanese researchers in order to encourage younger researchers in operator algebra theory and related fields. The prize is to be awarded every four years to a person age 40 years or younger either of Japanese nationality or primarily affiliated with a Japanese institution for outstanding contributions to operator algebra theory and related areas.

--- Huzihiro Araki, chair, Operator Algebra Prize Committee

*The prize of 2004 was given to Masaki Izumi.*

MASAKI IZUMI of Kyoto University has been awarded the second Operator Algebra Prize for his outstanding contributions to the theory of subfactors and the classification of automorphisms of C^{*}-algebras, and thus to the advancement of operator algebra theory. The prize consists of a cash award of about US$3,000, a prize certificate, and a medal.

The Operator Algebra Prize was established in 1999 by initiatives and contributions from some senior Japanese researchers in operator algebra theory and related fields to encourage young researchers in these fields. The prize is awarded every four years to a person under forty years of age either of Japanese nationality or principally based in a Japanese institution for outstanding contributions to operator algebra theory and related areas.

--- Huzihiro Araki, Kyoto University

*The prize of 2008 was given to Narutaka Ozawa.*

Narutaka Ozawa of the University of Tokyo has been awarded the third Operator Algebra Prize for his outstanding contributions to the structure theory of type II_{1} von Neumann algebras related to the theory of discrete groups and thus to the advancement of operator algebra theory. The prize consists of a cash award of about US$3,000, a prize certificate, and a medal. Ozawa has given a series of stunning results on the structure of operator algebras in connection with discrete groups. He first gave a characterization of exactness of discrete groups, which showed groups claimed by Gromov are not exact, thus solving a long-standing open problem. He has further introduced the notion of a solid von Neumann algebra, which means that the relative commutant of any diffuse subalgebra is injective, and has shown that various group von Neumann algebras are solid. This is a far-reaching generalization of a famous theorem of Ge and other related results and has been used by many other people, who have combined this technique with Popa's to get many very strong results on tensor product decompositions of factors and Cartan subalgebras in factors. Ozawa also has other well-known results on injective operator spaces, state spaces of C^{*}-algebras, and nonexistence of a separable universal II_{1} factor.

The Operator Algebra Prize was established in 1999 by initiatives and contributions from some senior Japanese researchers in operator algebra theory and related fields to encourage young researchers in these fields. The prize is awarded every four years for outstanding contributions to operator algebra theory and related areas to a person under forty years of age either of Japanese nationality or principally based in a Japanese institution.

--- Fumio Hiai, Chair, Operator Algebra Prize Committee

*The prize of 2012 was given to Hiroki Matui.*

Hiroki Matui of Chiba University has been awarded the fourth Operator Algebra Prize for his outstanding contributions to the interaction between topological dynamical systems and C^{*}-algebras and classification of group actions on C^{*}-algebras. The prize consists of a cash award of about US$4,000, a prize certificate, and a medal.

The Operator Algebra Prize was established in 1999 by initiatives and contributions from some senior Japanese researchers in operator algebra theory and related fields to encourage young researchers in these fields. The prize is awarded every four years to a person under forty years of age either of Japanese nationality or principally based in a Japanese institution for outstanding contributions to operator algebra theory and related areas.

--- Yasuyuki Kawahigashi, Chair, Operator Algebra Prize Committee

*The prize of 2016 was given to Yoshikata Kida.*

Yoshikata Kida of the University of Tokyo has been awarded the fifth Operator Algebra Prize for his outstanding contributions to interactions between ergodic theory and geometric group theory, and applications to theory of operator algebras. The prize consists of a cash award of about US$3,000, a prize certificate, and a medal.

The Operator Algebra Prize was established in 1999 by initiatives and contributions from some senior Japanese researchers in operator algebra theory and related fields to encourage young researchers in these fields. The prize is awarded every four years to a person under forty years of age either of Japanese nationality or principally based in a Japanese institution for outstanding contributions to operator algebra theory and related areas.

--- Yasuyuki Kawahigashi, Chair, Operator Algebra Prize Committee