The original tsunami was the origin of Japan. A big tsunami came and uncovered the islands of Japan. It's the origin of all life, as far as Japanese people are concerned.
This tsunami was also the origin of Genji (げん), from "The Tale of Genji." Just think, without this origin, Japan wouldn't exist and neither would the first Japanese heartthrob, Genji!
Currently there are no similar looking kanji which exist in the WaniKani learning system