Shikoku Shinkansen Plan Revived After 53 Years

The Ministry of Land, Infrastructure, Transport and Tourism announced on August 7 that it would begin basic studies of proposed Shinkansen networks in Shikoku and eastern Kyushu.

Shikoku is currently the only one of Japan's four main islands without Shinkansen service.

The announcement does not mean construction has been approved. The projects remain at the preliminary study stage, where potential routes, station locations and expected passenger demand will be examined before any decision is made on whether to proceed to more detailed legally required studies.

The move nevertheless marks the first major advance in plans that have remained largely dormant for more than half a century.

The original Shikoku Shinkansen concept, dating back to the era of Prime Minister Kakuei Tanaka, envisioned a route from Shin-Osaka through Awaji Island and Shikoku before continuing across to Oita in Kyushu.

That ambitious proposal has become increasingly difficult to justify because of construction costs and uncertainty over demand.

Attention has instead shifted toward what is being described as "Shinkansen in Shikoku," centered on a network extending from Okayama to the prefectural capitals of Shikoku.

Local governments in all four Shikoku prefectures and regional business groups have been pushing for the Okayama-based route, and the transport ministry's decision to begin studies has been viewed locally as recognition of that support.

If the network were completed, travel from Shin-Osaka to several major Shikoku cities could fall to around 90 minutes.

Travel to Matsuyama and Kochi could be roughly halved compared with current journey times. Tokushima, which can now be reached from Osaka in around 2 1/2 hours by road via Awaji Island, could also become about an hour closer.

The shorter travel times could make day trips from Kansai to destinations such as Matsuyama and Kochi more practical and significantly reduce the psychological distance between Shikoku and the Osaka region.

Within Shikoku itself, proponents say Tokushima, Takamatsu, Matsuyama and Kochi could each be connected in roughly two hours, making movement between the island's major cities substantially easier.

The potential economic impact within Shikoku has been estimated at around 16.9 billion yen a year.

One major reason the Okayama route is considered more realistic is the Seto Ohashi bridge connecting Honshu and Shikoku.

The bridge was constructed with space that could accommodate Shinkansen tracks, meaning part of the infrastructure needed for a high-speed railway already exists.

A similar opportunity once existed on the route between Kobe and Awaji Island.

The Akashi Kaikyo Bridge was originally considered as a combined road-and-rail crossing, like the Seto Ohashi and the Onaruto Bridge. However, the economic slowdown following the oil shocks and the financial problems of the former Japanese National Railways weakened prospects for the Shikoku Shinkansen.

Authorities ultimately prioritized road construction, and the Akashi Kaikyo Bridge was built only for highway traffic.

That decision makes a Shinkansen route through Awaji Island much more difficult today and has strengthened the case for accessing Shikoku through Okayama and the Seto Ohashi.

The current process remains at an early stage.

The initial basic study will examine broad route options, possible station locations and estimated demand. If the project advances, a more detailed statutory investigation would examine requirements such as tunnels and bridges and calculate construction costs.

Only after those stages could political approval lead to adoption of a formal development plan and elevation to the status of a construction Shinkansen project.

That means Shikoku remains well behind projects already in the development process, including the proposed extension of the Hokuriku Shinkansen from Tsuruga toward Osaka.

However, the prolonged debate over the Hokuriku route has also raised the possibility that progress on other proposed Shinkansen projects could eventually accelerate.

A central issue for Shikoku will be whether to build a full-standard Shinkansen or adopt a lower-cost alternative.

Local governments are seeking a full-standard line with dedicated double-track infrastructure, new rolling stock, no level crossings and maximum speeds of around 260 kilometers per hour, similar to other Shinkansen lines built under Japan's development program.

Such a system would provide the greatest travel-time reductions but would also be the most expensive.

Government documents have suggested that future Shinkansen projects could instead consider lower-cost approaches in areas with limited demand.

Options could include building sections with a single track and passing facilities or adopting a mini-Shinkansen system similar to those used in Akita and Yamagata, where trains can continue onto converted conventional railway lines.

Such measures could reduce construction costs while avoiding the need for passengers to transfer between trains, although speeds would be lower on conventional sections and level crossings would remain.

How far local authorities are willing to compromise on their demand for a full-standard system could significantly affect the speed and feasibility of the project.

A first section as far as Takamatsu could be comparatively easier to develop because a substantial portion of the Okayama-Takamatsu corridor already uses the Seto Ohashi infrastructure designed with future railway capacity in mind.

The government is also studying the East Kyushu Shinkansen, another long-discussed project.

That proposal would run along the eastern side of Kyushu through Oita and Miyazaki before reaching Kagoshima.

Supporters argue that such a route could provide an alternative transport corridor during disasters, particularly when existing railway infrastructure is disrupted.

Demand, however, is a major concern.

Passenger numbers on conventional railway sections near the Oita-Miyazaki prefectural border have fallen to around one-third of their level about 30 years ago, with some trains carrying passenger numbers comparable to a single bus.

At some remote stations, only a handful of trains stop each day, illustrating the difficulty of demonstrating sufficient demand for the enormous investment required for a Shinkansen.

Shikoku faces a different but related concern over what is known as the "straw effect."

High-speed rail can strengthen regional economies by improving access, but it can also draw people, spending and business activity toward larger cities.

If Shin-Osaka and Shikoku's major cities were only around 90 minutes apart, more people and money could flow toward Kansai.

Tourism could also be affected. Easier day trips might increase visitor numbers while reducing overnight stays, potentially hurting hotels and other businesses that depend on longer visits.

Supporters of the project therefore face a broader question beyond whether a Shinkansen can be built: whether the new railway can be designed in a way that strengthens Shikoku's economy rather than accelerating the concentration of activity in larger metropolitan areas.

Because Shikoku and eastern Kyushu would be among the last regions in Japan to receive Shinkansen service, planners may have the advantage of learning from the experiences of cities where high-speed rail has already produced both benefits and unintended economic effects.

Source: YOMIURI