In 1990, during the heyday of the soap bubble economy and thanks to a change in taxation in Japan, the road was opened for the production of large high-class cars. Diamante, launched in 1990, opened this road. Its body had dimensions that did not fit into the head of the then Japanese; for example, the width was 1775 mm. It was equipped with 2-, 2.5- and 3-liter V-shaped 6-cylinder engines. This car completely turned the Japanese view on the body of the 3rd size. The classic “box-shaped” body design and hood shape, giving the car a resemblance to BMW models that were extremely popular at the time, were the main reasons for the rise in Diamante's popularity.
It was the only car of that period, which was equipped with the latest science and technology. Here, an automatic valve clearance system was used, as well as 4 electronic systems: 4WS, TRC, ABS and Easy Drive. As a result of partial changes in 1992, the new 4-speed automatic transmission INVECS began to be used on Diamante. There is also a version of hard top - Sigma, which, in principle, is no different from Diamante.