The first section of the line, from Komuro to Shin-Kamagaya, opened in March 1979, including a temporary connection to the
Shin-Keisei Line at Kita-Hatsutomi. As other tracks were connected, it changed its name to "Hokusō Kōdan Line" in April 1987. Over 17 years later, the railway properties of the HDC corporation transferred to , on July 1, 2004, and the whole line was renamed as the Hokusō Line.
Western section This section was planned as a railway access to
Chiba New Town. Initially proposed by a committee of the then
Ministry of Transport, the route was numbered "Line 1", as the northern extension of
Tokyo Metropolitan Bureau of Transportation (Toei) Line 1 (present
Asakusa Line) to Komuro area of Chiba New Town. In 1979 the first phase of this section between and opened. The through-operation via
Shin-Keisei Line to began, on a temporary basis until the second phase of this section could connect the town directly to the
Keisei and
Asakusa Line network. The second phase section to on the
Keisei Main Line opened in 1991, and through-operation began. In the following year, Shin-Keisei included Shin-Kamagaya Station as a transfer station, and abandoned the temporary route.
Eastern section The section east of Komuro was initially the eastern part of a once-planned (II, apart from the first which opened the
Tōbu Noda Line and the
Kururi Line) as an extension of Line 10 (
Shinjuku Line). The line was to be built from via to parallel to the line above, then to terminate at present . The first section between Komuro and was opened in 1984, and the operations were commissioned to the present Hokusō Railway. • March 9, 1979: Hokusō Line (first phase) of – . Through-operation via
Shin-Keisei Line to on temporary basis. • March 19, 1984: of (HUDC onwards) Komuro – • April 1, 1987: On the section of Komuro – Chiba New Town Chūō, Hokusō Development Railway became the Category-2 Railway Business operator, while HUDC became Category-3 Railway Business. On the commencement of the , Act No. 92 of 1986) for the privatization of the
Japan National Railways. Simultaneously, the entire stretch was renamed to • March 31, 1991: Hokusō Line (phase 2) – . Through-operations by four parties (Hokusō,
Keisei Electric Railway,
Tokyo Metropolitan Bureau of Transportation (Toei),
Keihin Electric Express Railway (Keikyū)) began. • July 4, 1992: Shin-Keisei opened Shin-Kamagaya Station. Through-operation to Shin-Keisei terminated. The section of Kita-Hatsutomi – Shin-Kamagaya was abandoned. • April 1, 1995: Chiba New Town Chūō – Inzai-Makinohara, as Hokusō Cat-2, HUDC Cat-3 • 1999: HUDC reorganized to the (HDC onwards), continued state of Cat-3 of the line. • July 22, 2000: Inzai-Makinohara – Imba Nihon-idai, as Hokusō Cat-2, HDC Cat-3. Present stretch completed. • July 1, 2004: Railway properties of HDC transferred to , and the whole line was renamed as the Hokusō Line.
Extension to Narita Airport After the abandonment of the planned
Narita Shinkansen, routes of rapid transit to
Narita Airport had long been discussed. For a utilization of partially completed tracks of the Shinkansen, JR East and Keisei lines to were realized. A much faster line had long been needed, and for that purpose the first priority was the Keisei – Hokusō route. In 2001, a new Cat-3 entity, commenced building a new line connecting Imba Nihon-idai to the junction to which is a Cat-3 company of existing access railways, the tracks of the formerly planned Narita Shinkansen. The express trains are operated by Keisei as a Cat-2 operator with maximum speed at , the fastest among Japanese private railways (which was formerly shared with
Hokuetsu Express until the opening of the
Hokuriku Shinkansen in 2015) which enables a 34-minute journey from to Narita Airport. The line opened in July 2010.
Local subsidies Hokuso Railway fares are significantly higher than those of other private railways in the region. In 2013, a journey of on the Hokuso Line cost 540 yen, while a journey cost 720 yen. Equivalent journeys on the Keisei Main Line cost 250 yen and 360 yen respectively while equivalent journeys on JR East cost 210 yen and 380 yen respectively. The difference in fares is largely due to the debt burden remaining from the portion of the line built and owned by Hokuso Railway itself; this is also the case for the
Tōyō Rapid Railway Line and the
Saitama Rapid Railway Line, which are also known for having comparatively high fares. In 2009,
Chiba Prefecture and several municipalities along the line agreed with Hokuso Railway for an average fare reduction of 4.6% (25% for student commuter passes), in exchange for which they agreed to subsidize half of the estimated revenue loss of 600 million yen. The fare reduction was implemented in July 2010 at the time of the opening of the Narita Sky Access Line. In 2011 and 2012, the cities of
Shiroi and
Inzai elected new mayors on platforms of negotiating for further fare reductions and stopping public subsidies respectively; a third-party study commissioned by the two city governments concluded in August 2013 that the Hokusō Line would break even at more discounted fare levels without local subsidies. Hokuso, on the other hand, has argued that increased
consumption tax rates and capital expenditures related to upgrading the
Pasmo system will force them to raise fares in 2015. Additional fare reduction measures were implemented on 1 October 2022 which brought down regular fares by around 10% along with commuter passes being discounted by an additional 65%. ==References==