One two-car train was delivered in June 2018[2] for testing in preparation for full production and entry into revenue service.

[3] The interior features LED lighting and four-language passenger information displays.

JR Kyushu reports that the hybrid system consumes 20% less fuel than the diesel-hydraulic KiHa 66 and 67 trains, which were envisaged to be replaced by the YC1 series.

[7] Throughout 2020, twenty-four YC1 series cars were delivered from Kawasaki Heavy Industries' Hyogo plant.

[8][9][10][11] Since 23 September 2022, a majority of Nagasaki Main Line local and rapid services have been operated using YC1 series trains.