Section 5. Wartime Research and Production

Item 6. Truck Production and the Steel Shortage

In 1935, when the Automotive Department of Toyoda Automatic Loom Works, Ltd. launched the G1 truck, Japan's annual domestic steel production amounted to 3.81 million tons (3.74 million tons of regular steel, 70,000 tons of special steel). Most of the raw material for Japan's iron and steel production was provided from scrap metal, the consumption of which reached 2.98 million tons in that year. The industry relied on scrap metal imports of more than one million tons a year from the United States, but these were interrupted in 1940, sparking an increasingly serious iron and steel shortage in Japan. The pre-war, mid-war peak of iron and steel production was reached in 1943, with 7.65 million tons, for which 4.17 million tons of scrap metal was consumed (99 percent from domestically-produced sources).

In addition to this quantitative shortage, steel for automotive use also faced major problems in terms of quality. Aware of the importance of steel materials, Kiichiro Toyoda's initial policy was to establish a steelworks to carry out research and development into steel materials; when successful development of the necessary steel varieties was assured, their production would be commissioned to a specialist steel manufacturer. However, the material produced by steel manufacturers-who used scrap metal as their main raw material-was contaminated with surplus alloy constituents, so that the composition and properties of the steel varied between different manufacturers even for a steel variety of the same specification. Dimensions and shape were also subject to variation, making it unsuitable for mass production.

Therefore, if Toyota wanted to obtain steel material of confirmed quality, it would have to produce it in its own steelworks. In Kiichiro's opinion, the mass production of good quality automobiles required steel material of good machinability and excellent durability.1

In 1939, to cope with increased production at Toyota Motor Co., Ltd., the Steelmaking Department of Toyoda Automatic Loom Works took steps to increase production capacity: using space freed up after the completion of the Koromo Plant, two additional 4-ton electric furnaces were installed, which began operation in May of the same year.2

As mentioned previously, from January 1940 until the end of the year, the steelworks was under the guidance of the engineer Louis Henry Berry. In spring of that year, Shoichi Saito, Manager of the Auditing and Improvement Section, was posted to the steelworks, where he worked as interpreter and assistant to Berry, and in six months learned about grain size3 and other aspects of steel manufacturing technology.4

After listening to advice from Berry, Kiichiro came to realize that the purity of the steel manufacturing raw material was an important factor. To obtain pure raw material for steelmaking rather than scrap metal contaminated with other constituents, Kiichiro therefore sent Saito to mainland China in September 1940 on an investigative mission.5 At the same time as researching pure raw materials for steelmaking, Kiichiro explored various strategies to deal with the raw material shortage, but resolving the absolute shortage of steel materials proved difficult.

Truck development and production thus proceeded against a background of insufficiencies in both the quality and the quantity of steel material. In January 1940, the GB truck was upgraded. Among the improvements were an increase in engine output from 75 hp to 78 hp, improved engine cooling efficiency, and enhancements in the suspension area.

Meanwhile, the Ministry of Commerce and Industry's Automobile Technology Committee (established in August 1939), which was working on the creation of standard vehicle specifications, called for an increase in truck load capacity. In response, Toyota Motor Co., Ltd. took the decision to develop a new truck model based on a substantial upgrade of the GB truck. In March 1942, it began production of the KB truck with a 4-ton load capacity.

On July 14 of the next year, 1943, the Automobile Technology Committee officially decided the specifications of a wartime truck. Based on these specifications, Toyota Motor Co., Ltd. developed the KC truck and used it to replace the KB in November of the same year. To adapt to the steel shortage, the design of the KC truck achieved a saving of around 30 percent (260 to 300 kilograms) in the use of steel material compared to previous trucks. The chassis specifications of the KB and KC trucks are shown in Table 1-8.

Table 1-8. Specifications of the Model KB and Model KC Truck Chassis (1943)

Model KC Truck Chassis
Model KB Truck Chassis
Type B (3389 cc, 78 hp)
Type B (3389 cc, 78 hp)
6,150mm (total vehicle length)
Empty weight
'Toyota Truck Specification Sheet' (model KC), Toyota Truck Wheelbase 4.00 m catalog, 1943.
Excerpted from '2602 Toyota Truck Specification Sheet' (model KB), Toyota Truck Wheelbase 4.0 m catalog, April 1942.

To top of page