In a modern war, which is a war of movement and of aerial bombardment, the geographical position of the chief industries of a country, and hence their vulnerability to attack, becomes of prime importance. The westward orientation of Russian industry in the past has made it fairly vulnerable; and the industrial centres of the Leningrad and Moscow districts and the Ukraine continue to hold a major part of the productive capacity of the essential industries. For example, the Ukraine still accounts for between a half and two-thirds of the coal, iron ore and pig-iron production of the U.S.S.R. and for nearly three-quarters of the aluminium. Of oil production 90 per cent. still comes from the Caucasus region. In engineering and the manufacture of machine-tools Leningrad, Moscow and Kharkov still hold pride of place; Moscow as a centre of electrical engineering and machine-tools, Leningrad of shipbuilding and engineering, and Kharkov of heavy engineering. Nevertheless, there has taken place over the past ten years a shift in the location of Soviet industry towards the east which has considerably reduced its military vulnerability.