[flavio81]

The rotary was never invented by Mazda, it was invented in germany and applied first by NSU.

Then it was licensed to many manufacturers, among which there was Mercedes-Benz, which was the manufacturer who got solved first the apex seal problem, and in the late 70s with the C111 prototype car, the first manufacturer to create a side port wankel engine (which mazda would only show on the RX8 decades later) and a 4-rotor engine (which mazda would only show on the 787 racing car in 1991.

Then MB ditched the wankel engine because of low fuel efficience, something that ultimately led to mazda doing the same... in the 2000s.