The proportion of three-wheeled trucks that contributed to Japan's recovery after the war peaked at 72 percent of overall truck production in 1953. From that point on, small four-wheeled trucks began to take over. At the time, Japan's economy was enjoying a period of rapid growth and demand was quickly rising for comfortable four-wheeled trucks. Mazda, which had been producing small four-wheeled trucks in low volumes since 1950, did not let this opportunity pass by, and in April 1958 brought out the new Romper cab-over semi four-wheeler. This model had a robust body, superbly nimble performance and plenty of other attributes. It also shared all the latest technology that had been cultivated in the development of Mazda's three-wheeled trucks. The Romper had a 32.5ps water-cooled, twin cylinder engine and a one-ton load capacity. In March the following year (1959), Mazda introduced the D1100, equipped with an advanced water-cooled four-cylinder DHV engine delivering outstanding power (1-ton class, 46ps) as well as the D1500 (1.75-ton class, 60ps). The 1-ton 46ps model was the most powerful in its class and quickly earned a strong reputation, boosting Mazda's share of the small truck market from four percent in 1958 to more than double (ten percent) in 1959.
The D1100 and D1500 grew in popularity as the core models of Mazda's truck department, and in April 1962 the company launched an all-new D1500 (1-ton, 60ps) and a 2-ton truck, the D2000, with a newly developed 81ps engine. Then, in January 1964, after extensive market research involving customer interviews, Mazda evolved the E2000, which boasted a maximum load capacity of 2 tons. This model became the forerunner of the robust and popular Titan. Meanwhile, Mazda launched the B1500, its first pickup truck, in August 1961. By October 1965, it had developed into the Proceed, and although this marked the end of Mazda pickups in Japan, it is well-known that the B-series lived on to gain a strong foothold abroad. Symbolic of this is the Mazda BT-50, a new pickup with a direct-injection turbo-diesel engine that was unveiled at the 2006 Bangkok International Motor Show. The Mazda BT-50 won in the Best High-lifted Pickup 2,500cc at Thailand Car of the Year 2007 Awards.