Construction of Mammoth Tankers

In response to the Suez Canal Incident of 1956, shipbuilders began constructing mammoth tankers with capacities of 66,000 tons or more, which could be competitive even when traveling over routes via Capetown. Starting with the Universe Admiral (85,000-ton capacity) in 1956, Idemitsu then went on to build the third-generation Nissho Maru, at the time the world's largest tanker with a capacity of 139,000 tons.

Also, in August 1962 Idemitsu Tanker was established in the international tanker business, as Idemitsu began full-fledged participation in the maritime shipping business for the first time since the war. In December 1966, the Idemitsu Maru (209,000-ton capacity), the world's first 200,000-ton-class very large crude carrier (VLCC) was commissioned.
Together with securing a stable supply of crude oil through using its own vessels, Idemitsu's construction of large tankers also contributed to the development of the shipbuilding industry in Japan.