For model year 1990, the Debonair was joined by a new, more modern looking and sporting executive sedan, called the Mitsubishi Diamante (also known as the Sigma) in an attempt to keep Mitsubishi competitive with new executive sedans, such as the Honda Legend and other Japanese luxury sedans as the Debonair continued to be perceived as dated in appearance. The motivation to introduce a modern looking, executive level luxury sedan also took place in what has become known as the Japanese asset price bubble period that began after the Plaza Accord agreement in 1985.