[2] The trains are built by Kawasaki Heavy Industries to a "retro-future" concept, with black front ends intended to evoke images of a steam locomotive.

[2] Each vehicle is built at a cost of approximately 250 million yen, financed partially by national infrastructure investment subsidies.

[3] The first two pre-series sets, E11 and E12, were delivered to Takamatsu Depot from the Kawasaki Heavy Industries factory in Kobe in February 2014.

[8] In 2017, JR West borrowed two 8600 series sets to test the feasibility of pneumatic tilting on the Hakubi Line[9][10] for a new rolling stock type for its Yakumo limited express services.

[11] Three-car set E3 was delivered from Kawasaki Heavy Industries in January 2018,[12] entering service on 14 February.