Editing Shinkansen (section)

=== Proposed lines ===
[[File:Planned Shinkansen Map English 2021.svg|thumb|upright=1.2|Map of proposed Shinkansen lines]]
Many Shinkansen lines were proposed during the boom of the early 1970s but have yet to be constructed and have subsequently been shelved indefinitely.
* Hokkaido Shinkansen northward extension: Sapporo–Asahikawa
* {{Nihongo|Hokkaido South Loop Shinkansen|北海道南回り新幹線|Hokkaidō Minami-mawari Shinkansen}}: [[Oshamanbe]]–[[Muroran]]–Sapporo
* {{Nihongo|Uetsu Shinkansen|羽越新幹線}}: [[Toyama, Toyama|Toyama]]–Niigata–Aomori
** Toyama–Jōetsu-Myōkō exists as part of the Hokuriku Shinkansen, and Nagaoka–Niigata exists as part of the Jōetsu Shinkansen, with provisions for the Uetsu Shinkansen at Nagaoka.
* {{Nihongo|Ōu Shinkansen|奥羽新幹線}}: Fukushima–Yamagata–Akita
** Fukushima–Shinjō and Ōmagari–Akita exist as the [[Yamagata Shinkansen]] and [[Akita Shinkansen]], respectively, but as "Mini-Shinkansen" upgrades of existing track, they do not meet the requirements of the Basic Plan.
* {{Nihongo|Hokuriku-Chūkyō Shinkansen|北陸・中京新幹線}}: Nagoya–Tsuruga
* {{Nihongo|Sanin Shinkansen|山陰新幹線}}: Osaka–Tottori–Matsue–Shimonoseki
* {{Nihongo|Trans-Chūgoku Shinkansen|中国横断新幹線|Chūgoku Ōdan Shinkansen}}: Okayama–Matsue
* {{Nihongo|Shikoku Shinkansen|四国新幹線}}: Osaka–Tokushima–Takamatsu–Matsuyama–Ōita
* {{Nihongo|Trans-Shikoku Shinkansen|四国横断新幹線|Shikoku Ōdan Shinkansen}}: Okayama–Kōchi–Matsuyama
** There have been some activity regarding the Shikoku and Trans-Shikoku Shinkansen in recent years. In 2016, the Shikoku and Trans-Shikoku Shinkansen were identified as potential future projects in a review of long-term plans for the Shikoku area and funds allocated towards the planning of the route.<ref>{{cite news |title=新幹線誘致、オ– ル四国で 4県や四経連で新組織結成 |url=https://www.nikkei.com/article/DGXLZO18571700W7A700C1LA0000/ |access-date=21 February 2019 |publisher=日本経済新聞}}</ref> A profitability study has also been commissioned by the city of [[Ōita (city)|Oita]] in 2018 that found the route to be potentially profitable<ref>{{cite news |title=豊予海峡ル –ト・新幹線案 １日６８００人利用で黒字 大分市試算 [大分県] |language=ja |trans-title=Toyoyo Strait Route / Shinkansen Proposal Profitable for 6800 people a day Oita City Estimate [Oita Prefecture] |publisher=西日本新聞 |url=https://www.nishinippon.co.jp/nnp/oita/article/385544/ |access-date=21 February 2019 |archive-url=https://web.archive.org/web/20210512114900/https://www.nishinippon.co.jp/item/n/385544/ |archive-date=12 May 2021}}</ref>
* {{Nihongo|East Kyushu Shinkansen|東九州新幹線|Higashi-Kyushu Shinkansen}}: Fukuoka–Ōita–Miyazaki–Kagoshima
* {{Nihongo|Trans-Kyushu Shinkansen|九州横断新幹線|Kyushu Ōdan Shinkansen}}: Ōita–Kumamoto

In addition, the Basic Plan specified that the Jōetsu Shinkansen should start from [[Shinjuku Station|Shinjuku]], not [[Tokyo Station]], which would have required building an additional {{convert|30|km|mi|abbr=on}} of track between Shinjuku and Ōmiya. While no construction work was ever started, land along the proposed track, including an underground section leading to Shinjuku Station, remains reserved. If capacity on the Tokyo–Ōmiya section proves insufficient at some point, construction of the Shinjuku–Ōmiya link may be reconsidered.

In December 2009, then transport minister [[Seiji Maehara]] proposed a bullet train link to [[Haneda Airport]], using an existing spur that connects the [[Tōkaidō Shinkansen]] to a train depot. [[JR Central]] called the plan "unrealistic" due to tight train schedules on the existing line, but reports said that Maehara wished to continue discussions on the idea.<ref>{{Cite news|title= Maehara sounds out JR Tokai over shinkansen link for Haneda airport|newspaper= Japan Today |date=28 December 2009 |url= http://www.japantoday.com/category/national/view/maehara-sounds-out-jr-tokai-over-shinkansen-link-for-haneda-airport |access-date=28 December 2009 }}{{dead link|date=May 2018 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> The succeeding minister has not indicated whether this proposal remains supported. While the plan may become more feasible after the opening the Chūō Shinkansen (sometimes referred to as a bypass to the Tokaido Shinkansen) frees up capacity, construction is already underway for other rail improvements between Haneda and Tokyo station expected to be completed prior to the opening of the [[2020 Tokyo Olympics]], so any potential Shinkansen service would likely offer only marginal benefit. Despite these plans ultimately not being realized (owing in part due to the effects of the [[COVID-19 pandemic in Japan|COVID-19 pandemic]]), rail projects in the vicinity of Haneda Airport, including the [[Haneda Airport Access Line]] and the [[Tokyo Rinkai Subway Line]], continue to undergo planning.<ref>{{cite web |date=21 January 2021 |title=JR East's Haneda Airport Access Line to Open in FY 2029 |url=https://www.nippon.com/en/news/yjj2021012001065/ |access-date=4 January 2023 |archive-date=25 January 2021 |archive-url=https://web.archive.org/web/20210125172245/https://www.nippon.com/en/news/yjj2021012001065/ }}</ref>