The first domestically produced bus after World War II—the birth of the B1 large bonnet bus

In 1945, the GHQ (General Headquarters of the Allied Forces) decided that restoration of the traffic and transportation system should be a top priority in the reconstruction of cities that had fallen into ruin during the war, and granted corporations permission to promptly produce trucks and buses for civilian use. This was on September 25, just over a month after the war ended. Mitsubishi was one of the first companies to respond.

Mitsubishi produced 4 ton KT1 trucks in July of 1946, and B1 buses in November of the same year. These B1 buses were the first buses produced in Japan following World War II.

B1 buses were modeled on the B46, which had been delivered to the Ministry of Railroads and the South Manchuria Railroad and had earned a great reputation during the war. The new B1s were large bonnet (cab-behind-engine) buses, equipped with 120 PS GA gasoline engines.

Due to a severe fuel shortage, the pace of diesel engine development was increasing. In 1948, Mitsubishi developed the DB0 diesel engine, which was a 6 cylinder, water-cooled, in-line, 4 cycle, pre-combustion engine producing 100 PS. This technology later developed into the creation of the DB engine series, which supported Fuso's postwar truck and bus development.

By 1950, 500 B1 bonnet buses had been produced. On the other hand, the MB46 large electric bus was developed in collaboration with [Mitsubishi Electric], [Japan Storage Battery], and [Nihon Kentesu] in 1947, and 107 were produced by 1948.

The era of the large sightseeing bus

At the end of 1949, the B2 bonnet bus was introduced. It had a redesigned B1 front with increased passenger capacity and PS. Originally, the B2 was equipped with a DB0 engine, but this engine was replaced by the 130 PS DB5 diesel engine in 1951.

By 1958, a total of 3,762 B2 buses, including both the B25 and B200, were produced, and Fuso's bonnet buses were seeing their best days. On the other hand, rear engine buses, which had been under development for the future, had been completed as the R1 series in 1950.

R1 buses were 11 m in length with a passenger capacity of 79 and a horizontally mounted rear engine. They were the largest buses in Japan in those days. The R2, which had a horizontally mounted rear engine with revolutionary cab space, was introduced in 1954, and increased Mitsubishi Fuso's share of the large bus market.

Transition from bonnet buses to rear engine buses

The B1 large bonnet bus was introduced.	The B2 bus with a redesigned B1 front and a 130 PS DB5 diesel engine.
The B25 bonnet bus developed in 1949.	The R2 bus, equipped with a 130 PS DB7 rear engine mounted horizontally.

Fuso's quick recovery in truck development became the driving force of Japan's reconstruction.

The first post-war Fuso truck, as mentioned previously, was the 4 ton KT1 truck produced at the Kyoto Machinery Works in July 1946.

KT1 trucks were modeled on the chassis and body of the YB40, the development of which ended in the creation of prototypes before World War II, and was equipped with a 62 PS GB38 gasoline engine.
By 1946, production of 7 ton B1 gasoline engine trucks began, and a diesel engine was incorporated in 1948.

After the dissolution of the "Zaibatsu", or conglomerates, in 1951, the first vehicle produced by Eastern Japan Heavy Industries, Ltd. ([Japan Mitsubishi Heavy Industries]) was the T31 bonnet truck with a cargo capacity of 8 tons.

The T31 employed a chassis frame specially designed for trucks and a DB5 engine with an increase in PS to 130.

The 4 ton KT1 truck was modeled after a YB40 truck prototype created before the war.

The B1 gasoline engine truck with a cargo capacity of 7 tons, shares the same chassis as the B1 bus.

The first T31 truck with a chassis frame specifically designed for trucks was introduced in 1951.

The W1 series became the basis for Mitsubishi Fuso's special vehicles.

In 1951, Mitsubishi's Kawasaki Plant developed and produced the W11, a 4 ton, all wheel drive (6 x 6) towing truck. Utilizing this W11 as a base, dump trucks with DB diesel engines were produced, and at the same time, W13 truck cranes and W14 six ton tractors were produced and introduced to the National Security Force and civil engineering companies.

The W1 series, which had started with W11 trucks, formed the foundation of Mitsubishi Fuso's specialized vehicles, such as towing trucks, dump trucks, crane carriers, and tractors.
The W2s, developed in 1953, were even larger all-wheel drive (6 x 6) trucks than the W1s, equipped with more powerful in-line, 6 cylinder, 200 PS, pre-combustion DH engines.

In 1946 after World War II when the B1 bonnet bus, Fuso's first post-war bus, was introduced. In those days, a high-class tobacco called "Peace" sold for 7 yen per 10 pack, "Asahi" sold for 1.65 yen per 20 pack, second-class Japanese sake sold for 18.96 yen per 1.8 liters, and 10 kg of rice sold for 28.16 yen.