The Japan Railways Group, more commonly known as JR Group (JRグループ Jeiāru Gurūpu), consists of seven for-profit companies that took over most of the assets and operations of the government-owned Japanese National Railways on April 1, 1987. Most of the liability of the JNR was assumed by the JNR Settlement Corporation.
The JR Group lies at the heart of Japan’s railway network, operating a large proportion of intercity rail service (including the Shinkansen high-speed rail lines) and commuter rail service. Despite JR East, JR Central, JR West and JR Kyushu now having full private ownership, Japanese people talk about “private railways” as if none of the JR Group companies (nor the third sector former JR lines) is part of them, since they are successors of Japanese National Railways (JR Hokkaido, Shikoku and Freight are still governed by Act for the Passenger Railway Companies and Japan Freight Railway Company [ja] (also known as the JR Companies Act) and are under control of JRTT.) Maps almost always denoted JR and private railways differently,
AloJapan.com