Nippon Steel Trading Co., the trading house that is approximately half-owned by Japan’s biggest steelmaker, Nippon Steel Corp., announced Thursday that two other trading houses affiliated with major steelmakers will participate in its e-commerce site, which will start operating Monday.

It said Sumikin Bussan Corp., an affiliate of Sumitomo Metal Industries Ltd., and Shinsho Corp., a unit of Kobe Steel Ltd., will join it in promoting the www.kouzai.com site, which principally targets customers in Japan, the company said.

NKK Trading Inc., an arm of NKK Corp., another major steelmaker, is considering taking part in the initiative soon, industry sources said.

The steel firms are apparently joining hands through their trading units to promote the site to counter a recent move by major trading houses to set up a similar Internet site designed to link suppliers and buyers.

Nippon Steel Trading’s site will enable buyers to negotiate with steelmakers after presenting their desired product specifications and prices.

A commission of 0.5 percent of the contract value will be charged.

Sumikin Bussan and Shinsho will not only participate in the site as suppliers of products from their steelmaker parents, but also take equity stakes in the company that operates the site, Nippon Steel Trading said.

The three companies are currently discussing what stakes Sumikin Bussan and Shinsho should take.

Nippon Steel Trading is also involved in an e-commerce site — www.livesteel.com — for overseas customers to sell the products of Nippon Steel and Iscore Ltd., a South African steelmaker.

The site is operated by Hong Kong-based LiveSteel Ltd., a firm equally owned by Nippon Steel Trading and Macsteel International Holdings BV, a Dutch steel trader owned by Iscore.