Mass production of Fordson model F started in 1917. The Fordson came at the end of the First World War with its manpower shortages in agriculture, and utilizing Ford's assembly line techniques to produce a large number of inexpensive units, it quickly became the dominant model. Three-quarters of a million tractors were sold in the U.S. alone in the first ten years. Thousands were shipped to the United Kingdom and the Soviet Union where local production was soon started. Fordson had a 77% market share in the U.S. in 1923 before facing increased competition from International Harvester Corp.