| Roles | Competed in Olympic Games • Coach |
|---|---|
| Sex | Male |
| Full name | Seiji•Oko |
| Used name | Seiji•Oko |
| Original name | 大古•誠司 |
| Born | 15 February 1948 in Kawasaki, Kanagawa (JPN) |
| Measurements | 194 cm / 92 kg |
| Affiliations | Nippon Kokan KK |
| NOC | Japan |
| Medals | OG |
| Gold | 1 |
| Silver | 1 |
| Bronze | 0 |
| Total | 2 |
| Games | Discipline (Sport) / Event | NOC / Team | Pos | Medal | As | |
|---|---|---|---|---|---|---|
| 1968 Summer Olympics | Volleyball (Volleyball) | JPN |
Seiji Oko | |||
| Volleyball, Men (Olympic) | Japan | 2 | Silver | |||
| 1972 Summer Olympics | Volleyball (Volleyball) | JPN |
Seiji Oko | |||
| Volleyball, Men (Olympic) | Japan | 1 | Gold | |||
| 1976 Summer Olympics | Volleyball (Volleyball) | JPN |
Seiji Oko | |||
| Volleyball, Men (Olympic) | Japan | 4 |
| Games | Sport (Discipline) / Event | NOC / Team | Pos | Medal | As | |
|---|---|---|---|---|---|---|
| 1992 Summer Olympics | Volleyball (Volleyball) | JPN |
Seiji Oko | |||
| Volleyball, Men (Olympic) | Japan | 6 |