Formed only a dozen years ago, DDI Corp is already the second largest Japanese telephone company, and to further its expansion it wants to buy a big chunk of the capacity of a planned undersea fibre optic cable that will girdle Japan. It has agreed to buy 20% of the transmission capacity of the cable, which is to be laid around Japan by mid-1999 and is being installed by Kokusai Denshin Denwa Co. Japanese telephone operators have long been restricted to specific segments of the market, such as local, domestic long-distance or international operations but under plans to increase competition, that will break down. The new cable, to be built at a cost of around $900m, will help meet growing Japanese demand for telephone services, including Internet access. The cable will loop around Japan’s three main islands and carry 1.2 million phone lines, with voice and data transmission capacity of 100G-bits a second. Nippon Telegraph & Telephone Corp is expected to announce international operations via a subsidiary in the next few days as part of its restructuring.