The Mazda RX-3 (Savanna in Japan) was produced by Toyo Kogyo between 1971 and 1978. For the original 1971 version, Mazda fitted its 10A rotary engine to create a separately marketed product line sold in coupé, sedan, and station wagon guises. Shortly after its release, Mazda came up with a new process called Transplant Coating Process (TCP) which utilised sprayed-on steel to coat the engine rotor tips with chrome, which greatly increased engine life. All Mazdas then had their die-cast rotor housings coated with this new process. The rotary engine had financial advantages to Japanese consumers because the smaller engine displacement (below 1.5 litres) meant significantly reduced annual road tax, at the same time delivering more power than the traditional in-line engines. The RX3’s rotary engine was upgraded to the larger 12A rotary in the GT model introduced in September 1972, and eventually this became the standard engine across the entire model range. Coupé sales accounted for over half of total sales.