InfrastructurePosted 09/14/202609/14/2026 at 8:05 pm@ThePinGang To timeline

Ministry of Land, Infrastructure, Transport and Tourism

Starts 03/11/2011 CONFIRMED 75% CONFIDENCEThe seawall program has no single completion date and remains partly unfinished as of 2026, so this pin is dated to the 11 March 2011 Tōhoku tsunami — the confirmed, exact date of the disaster that led Japan to commit to building it (construction of the network itself began in 2012, per contemporary sources).^[1]

Start: Mar 11, 201190% CONFIDENCEfrom the source

Japan Decides to Wall Off Its Coast After the Tōhoku Tsunami

Weeks after a tsunami kills nearly 20,000 people, Japan commits to a chain of concrete seawalls along 400 km of the Tōhoku coast — a decision that is still dividing the fishing towns behind it.

The 11 March 2011 Tōhoku earthquake and tsunami killed nearly 20,000 people and devastated the coasts of Iwate, Miyagi and Fukushima.
Japan’s reconstruction plans committed to rebuilding and raising the coast’s seawalls, and construction of the wider network began in 2012 under the Ministry of Land, Infrastructure, Transport and Tourism.
As of 2026 the program has built about 432 km of seawalls at a cost of roughly ¥1.4 trillion ($8.2 billion), with some sections still under construction or contested by the towns behind them.

@ThePinGang

Cost $8.2B

References 475% CONFIDENCE

The first entry is always the pin's source. Overall confidence is a weighted average of how firmly each reference supports the start and end times used above; a reference counts half as much for every 180 days older than the newest.

[1]90%
youtube.com/watch?v=Eg0djVfKXU8
youtube.com· Posted Sep 14, 2026· Starts Mar 11, 2011 ✓· 34% of score
The seawall program has no single completion date and remains partly unfinished as of 2026, so this pin is dated to the 11 March 2011 Tōhoku tsunami — the confirmed, exact date of the disaster that led Japan to commit to building it (construction of the network itself began in 2012, per contemporary sources).
[2]60%
Ministry of Land, Infrastructure, Transport and Tourism — Wikipedia
en.wikipedia.org· Added Sep 14, 2026· 34% of score
Wikipedia's page on Japan's infrastructure ministry does not actually mention the Tohoku seawall program at all, focusing only on the ministry's organizational structure, so it offers only tangential institutional context rather than direct confirmation of the pin's claim.
[3]75%
Coastal Japan turns to forests to blunt tsunami risks — Eco-Business
eco-business.com· Published Aug 20, 2026· 31% of score
Eco-Business's August 2026 report confirms Japan spent roughly $8.2 billion building 432 km of seawalls following the 2011 disaster, though it gives no specific completion date, supporting the pin's account without pinning down its own dated claim.
[4]76%
The B1M: Japan's 400 Kilometre Tsunami Shield
youtube.com· Published Mar 1, 2022· 0% of score

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