Born in Kobe, Japan, Kanaya first came to attention at the 1967 125cc Japanese Grand Prix, where he finished third behind Bill Ivy and Stuart Graham while riding for Kawasaki. He went on to win the 250cc class of the All Japan Road Race Championship in 1969, then joined the Yamaha factory racing team in 1970. By 1971 he had added the 90cc class and open class of the All Japan championship to his domestic victories.
Yamaha sent Kanaya to Europe in 1972 to contest the 250cc and 350cc world championship classes. His debut on the international stage produced immediate results: at the season-opening 250cc German Grand Prix at the Nürburgring — a demanding 22.9 km circuit — he won his first Grand Prix on a standard Yamaha 250 TD3, surprising more established rivals. He scored three further podiums that year, ending the season ranked 11th in the 250cc class and 8th in the 350cc class, with a 4th place in his only 500cc outing at the Belgian Grand Prix.
For 1973, Yamaha elevated Kanaya to partner 1972 250cc world champion Jarno Saarinen on the new four-cylinder YZR500 in the premier 500cc class while also contesting 250cc on the water-cooled YZR250. The season opened promisingly: Kanaya followed Saarinen with three consecutive second places in the 250cc class and podium finishes in the 500cc class. The campaign was cut short when Saarinen was killed at the Italian circuit of Monza during the fourth round, prompting Yamaha to withdraw its entire factory team for the rest of the season and return Kanaya to Japan.
A planned return for 1974 alongside multi-time world champion Giacomo Agostini was derailed when Kanaya suffered serious injuries in the pre-season Daytona 200, forcing him to miss the entire world championship season during his recovery.
Kanaya came back for 1975, and his first race back — the season-opening 500cc French Grand Prix — produced a second-place finish, just 0.5 seconds behind teammate Agostini. At the third round of the championship at the fast Salzburgring circuit in Austria, he achieved a historic double victory, winning both the 350cc and 500cc classes of the Austrian Grand Prix. The 500cc win made him the first Japanese rider to win in that class at world championship level, and also marked the first 350cc world championship win for a Japanese rider. He also won the Macau Grand Prix that same year.
Despite scoring points in only four championship rounds — Yamaha again recalled him to Japan for test duties after his Italian podium — Kanaya still finished the 1975 season third in the 500cc world championship standings, behind Agostini and Phil Read of MV Agusta. At the Suzuka round of the 1975 All Japan Championship he broke the circuit lap record, lapping in 2 minutes 16.2 seconds against the existing mark of 2 minutes 20 seconds.
Kanaya returned to Daytona in 1976, qualifying on the front row in third position behind Kenny Roberts and Steve Baker before finishing seventh after a pit stop for a tyre change forced by wear issues. He continued competing in Japanese national racing and performing development work on Yamaha Grand Prix and production class race machinery. He retired from racing in 1982 after competing in the TBC Big Road Race and continued his development role for Yamaha.
Kanaya's career highlights the tension within Yamaha's structure of the early 1970s: he was good enough to win at the highest level of Grand Prix racing and to hold top-three championship positions, yet his primary value to the factory was as a development rider rather than a full-time international competitor. His 1975 Austrian Grand Prix victory remains a landmark moment in Japanese motorsport history — the first time a Japanese rider stood on top of the premier class podium at a world championship event. He died on December 19, 2013, at the age of 68.