The gimmick that allowed FTL travel in the Star Blazers (Space Cruiser Yamato) universe. Queen Starsha of Iscandar sent the design information to Earth along with her sister (who didn't survive the voyage) and an invitation. The invitation was to use the technology to build a ship capable of going to Iscandar and returning with the Cosmo DNA device that would rid the Earth of the radiation created by Gamilon planet bombs.
Whew, got that?
Apparently Earth had no FTL cpability of its own before the Gamilon war; the wave motion engine enabled Earth battleships to leave the solar system for the first time. True to human homicidal ingenuity, Earth scientists were able to reengineer the technology to create the fearsome wave motion gun, which basically turned Earth ships into BFGs (see also: money shot).
The first Earth ship with a wave motion engine was the Argo, surreptitiously built underneath and within the wreckage of the Japanese World War II battleship Yamato. (The Argo was simply called the Yamato in Japan.)