Japan Built a 400 km Wall Against the Sea. Was It Worth It?

After the 2011 tsunami, Japan rebuilt and raised about 400 km of seawalls along Iwate, Miyagi and Fukushima, at an estimated ¥1.35 trillion. Some are taller than a four-story building. Yet by design, a wave like 2011's would still go over the top. So what did the money buy? We follow two towns that made opposite bets, Taro with its 10 m "Great Wall" and Fudai with a 15.5 m floodgate everyone called too tall, and what happened to both on March 11, 2011. Every number in this video is sourced (below). Heights are in meters above mean sea level in Tokyo Bay (T.P.). The cost is a Reuters estimate; we found no official total. Cross-sections are SCHEMATIC unless marked to scale. Illustrations are not real places or people unless labelled; "IMAGINARY" marks a wall that was never planned. The 2011 death toll is the National Police Agency's figure as of 2026; town figures are from local reports. Read it: key figures, maps and every source → https://hankomaps.com/episodes/japan-... CHAPTERS 0:00 A wall the sea can still cross 1:04 A coast that keeps getting hit 2:41 Two towns, two bets 4:18 March 11, 2011 5:57 The decision 8:21 Built to lose 9:41 The other side of the wall 11:33 Was it worth it? SOURCES • Cost, ~395 km: Reuters (2018) https://emtv.com.pg/seven-years-after... • ~400 km, heights by prefecture: MLIT https://www.mlit.go.jp/river/kaigan/m... • 197 of 621 stretches changed: MLIT https://www.mlit.go.jp/river/kaigan/m... • Level 1 / Level 2: MLIT https://www.mlit.go.jp/river/kaigan/m... ; Central Disaster Management Council https://www.bousai.go.jp/kaigirep/cho... • Taro heights 10 / 14.7 / 16.3 m: Iwate Pref. https://www.pref.iwate.jp/_res/projec... • Fudai 22.6 m, 190 of 300 km damaged: Cabinet Office https://www.bousai.go.jp/kaigirep/cho... • 1896 and 1933: JMA Sendai https://www.jma-net.go.jp/sendai/know... ; https://www.jma-net.go.jp/sendai/know... ; MLIT https://www.mlit.go.jp/river/kaigan/m... • Taro wall and 185: https://bousaihaku.com/pdf/dptopics/n... ; https://www.bousaihaku.com/pdf/report... • Fudai and Mayor Wamura: Fudai Village https://www.bousaihaku.com/wp/wp-cont... ; Gizmodo Japan https://www.gizmodo.jp/article/floodg... • 15,901 dead, 2,519 missing: National Police Agency via Jiji https://www.nippon.com/en/news/yjj202... • Why walls fail: MLIT https://www.mlit.go.jp/river/shinngik... • Progress: Iwate https://www.pref.iwate.jp/_res/projec... ; Miyagi https://www.pref.miyagi.jp/documents/... • Residents: ABC Foreign Correspondent (2021) https://www.abc.net.au/news/2021-03-0... ; Matanle et al. (2019) https://eprints.whiterose.ac.uk/id/ep... • Oya, Kesennuma, Onagawa: MLIT https://www.mlit.go.jp/sogoseisaku/re... ; Jiji https://sp.m.jiji.com/english/show/13641 ; Reconstruction Agency https://www.reconstruction.go.jp/311k... • Nankai Trough: Cabinet Office https://www.bousai.go.jp/jishin/nanka... ; HERP https://www.static.jishin.go.jp/resou... • What to do: JMA https://www.data.jma.go.jp/fukuoka/ji... Drawings, maps and charts by Hanko. Map data: Natural Earth. Music: generated with Suno (Pro). Spotted an error? Say so in the comments or email hankomaps@gmail.com. Corrections go in the pinned comment. #Japan #Tsunami #Engineering