Nippon Steel & Sumitomo Metal Corp. says its lawsuit against South Korean steelmaker Posco has broader implications for other domestic businesses whose technology is leaked.

During the first session at the Tokyo District Court on Thursday, Posco categorically denied stealing technological secrets, but Nippon Steel & Sumitomo Metal claims it has solid evidence detailing the company's industrial espionage in the alleged theft of manufacturing knowhow related to a specialty steel product. It is pressing for ¥98.6 billion in damages and an injunction to block Posco from producing it.

The Japanese firm became the world's second-largest steelmaker with a 30 percent market share through the Oct. 1 merger of Nippon Steel Corp. and Sumitomo Metal Industries Ltd., while Posco has the fifth-largest global share, at around 20 percent. Each firm dominates its respective domestic market, and the two have also worked together as strategic partners since 2000 in research and product development.