[2] Test running began on the Ōu Main Line between Niwasaka and Itaya on 14 November 1990.

From 23 January 1991, test running began in conjunction with a newly converted 200 series 8-car K set on the Tōhoku Shinkansen between Sendai and Kitakami.

On 26 March 1991, the 400 series set S4 established a new Japanese speed record of 336 km/h (209 mph) on the Jōetsu Shinkansen in the Yuzawa Tunnel between Echigo-Yuzawa and Urasa.

[5] Source:[5] In terms of style, the 400 series were originally painted a medium silver grey with a darker roof and area around the cab windows and underframe.

However they were refurbished and repainted between 1999 and 2001, with a higher area of dark bluish-grey on the underside, coming up almost to the side windows, and separated from the silver grey with a green stripe.

[10] The first eleven sets to be withdrawn were all cut up at Sendai General Depot, but one car (Green car 411-3) of the last set to be withdrawn, L3, was stored at the former Fukushima depot before being moved to Omiya in Saitama Prefecture in December 2017 where it's preserved at the Railway Museum.