Japanese dam builder Hitachi Zosen has developed a seawater barrier that deploys automatically when tsunami waves approach shorelines.
It's based on Hitachi's air-powered flap gates, which lie at the bottom of harbors and close them off in the event of a major change in sea level.
Neo Rise (from "no energy, no operation, rising seawall") is set up on land. It runs on hydraulic power associated with riding tides and closes automatically, protecting shoreline communities; it can also be operated manually. It's designed as simply as possible to avoid mechanical failures and high maintenance costs, according to Hitachi.
Balancing on several tectonic plates, Japan is one of the most earthquake-prone countries in the world, with more than 130,000 quakes logged in 2005. Only some of them are felt by people and fewer cause tsunamis, but the destructive waves are a serious threat to Japanese coastlines.