Outside the town of Yongin, 40 kilometres south of Seoul, an army of diggers is preparing for what South Korea’s president has described as a global “semiconductor war”.

The diggers are moving 40,000 cubic metres of earth a day, cutting a mountain in half as they lay the foundations for a new cluster of chipmaking facilities that will include the world’s largest three-storey fabrication plant.

The 1,000-acre site, a $91bn investment by chipmaker SK Hynix, will itself only be one part of a $471bn “mega cluster” at Yongin that will include an investment of 300tn won ($220bn) by Samsung Electronics. The development is being overseen by the government amid growing anxiety that the country’s leading export industry will be usurped by rivals across Asia and the west.