What is "nihonkai"

Nihonkai (日本海) commonly refers to:

• Sea of Japan, the body of water between Japan, Korea and Russia
• Nihonkai (train), an overnight sleeping car train service that runs along the Sea of Japan coastline

The is a seasonal overnight train which is operated by the East Japan Railway Company (JR East). The train runs overnight between Osaka Station and Aomori Station using the Tōkaidō Main Line, Kosei Line, Hokuriku Main Line, Shinetsu Main Line, Uetsu Main Line, and Ōu Main Line.

From the start of the March 17, 2012 timetable revision, regular operations of the Nihonkai were discontinued, with services operating during busy seasonal periods only.