If you think Japan is small, imagine how small it used to be. You may not be aware of this, but Japan is a lot bigger than it used to be, thanks to a phenomenon called landmass growth.
This geological process, more accurately described as a mutation, has been accomplished over hundreds of years of reclaiming land.
Kantakuchi, reclaimed land from the sea, may bring to mind some of the well-known man-made islands in Japan's Seto Inland Sea, such as Rokko Island off Kobe and the island in Osaka Bay that Kansai Airport was built on. But there is a lot more reclaiming going on that is little known.