The was a seasonal overnight train which was operated by the East Japan Railway Company (JR East). The train ran 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. While JR East has not formally announced its discontinuation, no services have operated since January 2013, Sometimes it either connect to Sapporo or Hakodate.
Operations
The Nihonkai operated between Osaka Station and Aomori Station on the following lines: Tōkaidō Main Line (JR Kyoto Line) Kosei Line Hokuriku Main Line Shinetsu Main Line Uetsu Main Line Ōu Main Line
There were two trains which operated daily. The journey time was around fifteen hours, depending on the exact route taken.
Formation
Locomotive
The Nihonkai was hauled by a JNR Class EF81 electric locomotive based at Tsuruga and operated by JR West Fukui Operations Center.
Passenger cars
24 series cars based at JR East Aomori depot
Generator car: Kani 24
Car No. 1: Orone 25-300: Class A single deluxe private compartments
Car No. 2: Ohane 25: Class B open compartment couchettes
Car No. 3: Ohane 25: Class B open compartment couchettes
Car No. 4: Ohanefu 25: Class B open compartment couchettes
Car No. 5: Ohanefu 25: Class B open compartment couchettes
Car No. 6: Ohane 25: Class B open compartment couchettes
Car No. 7: Ohane 25: Class B open compartment couchettes
Car No. 8: Ohanefu 25: Class B open compartment couchettes
Car Nos. 9-11: Ohane 25: Class B open compartment couchettes
Car No. 12: Ohanefu 25: Class B open compartment couchettes
During the off-season, Car Nos. 9-12 are not used.
Designated stops
●：Stop
↓・↑：Pass, does not stop
or indicates areas where the Class B cars can be used as a normal (non-sleeper) Limited Express seat. indicates a Standing Seat Limited Express Ticket is required. indicates a Reserved Seat Ticket is required.