"STAR21" was the name given to the Class 952/953 (952・953形) 9-car experimental Shinkansen train developed in 1992 by the East Japan Railway Company (JR East) in Japan to test technology to be incorporated in next-generation shinkansen trains operating at speeds of 350 km/h (217 mph) or higher.

[1] The front-end design of the two driving vehicles (952-1 and 953–5) were slightly different, although both used a wedge-shaped profile with little lateral taper.

[6] In 1993, the train was modified with the addition of motors to all axles, increasing its overall rating to 4,620 kW (6,200 hp).

This record stood until it was broken by JR Central's "300X" experimental train in July 1996.

[1][4] End car 952-1 is preserved outdoors at the RTRI large-scale wind tunnel test facility in Maibara, Shiga, first displayed to the public on 10 October 1998.