Series 1 RX-7 (1978–1980) is commonly referred to as the "SA22C" from the first alphanumerics of the vehicle identification number. This series of RX-7 had exposed steel bumpers and a high-mounted indentation-located license plate, called by Werner Buhrer of Road & Track magazine a "Baroque depression." In Japan it was introduced in March 1978, replacing the Savanna RX-3. The lead designer at Mazda was Matasaburo Maeda, whose son Ikuo would go on to design the Mazda2 and Mazda RX-8.
Source: Wikipedia (original)