National Railway Chiba Motive Power Union is a Japanese trade union, which is usually referred to as Doro-Chiba . It has also been referred to as the Chiba Motormen's Union in English. It split from the National Railway Motive Power Union (Doro) in 1979.

The Sanrizuka Struggle is a series of civil conflicts and riots involving the Japanese government and the agricultural community of Sanrizuka, comprising organised opposition by farmers, local residents, and leftist groups to the construction of Narita International Airport. The struggle stemmed from the government's decision to construct the airport in Sanrizuka without the involvement or consent of most area residents.