Rotary engine development began at Mazda in 1961, and for the next six years presented nothing but problems and setbacks. The most serious of which was the appearance of chatter marks on the inner walls of the rotor housing. These marks were known to Mazda engineers as "nail marks of the Devil" and always appeared after a certain period of operation. After many trials, the engineers finally conquered this difficult problem by developing seals made of high-strength carbon infused with aluminum, and the Mazda rotary engine was born. As other automakers steadily abandoned the rotary engine, Mazda succeed in its commercialization. The Mazda Cosmo Sport was born from Mazda's tenacity and passion for rotary engine development.

The Mazda Cosmo Sport was formally announced at the Tokyo Motor Show in 1964. Thereafter, Mazda engineers continued to work on quality and durability improvements to produce more refined performance. After completion of the Miyoshi Proving Ground in June 1965, Mazda carried out continuous high-speed endurance tests, covering a total test-drive distance of 700,000 kilometers from the time development began.
The Mazda Cosmo Sport was eventually launched on May 30, 1967.
It was a real breakthrough for sports cars, reaping the benefits of a rotary engine with 491cc x 2 capacity, maximum power of 110ps, top speed of 185 km/h, a quarter-mile (400m) time of 16.3 seconds and low, flowing styling. At the time, the Mazda Cosmo Sport was the only sports car of its kind, and sold around 30 units per month. The Cosmo Sport also enjoyed success in international motorsport.
It is now 40 years since the Mazda Cosmo Sport was launched. The passion that created Mazda's history of rotary engine cars that started with the Mazda Cosmo Sport remains alive and well to this day.