Nippon Steel Corporation (新日本製鐵株式會社, Shin Nippon Seitetsu Kabushiki-gaisha^?) (TYO: 5401), also referred to as Shinnittetsu (新日鉄^?), was formed in 1970. Nippon Steel Corporation is the world's 4th largest steel producer by volume.

Nippon Steel was created by the merger of two giants, Yawata Iron & Steel (八幡製鉄 Yawata Seitetsu) and Fuji Iron & Steel (富士製鉄 Fuji Seitetsu). Beginning in early 1981, however, the company cut production and saw a sharp decline in profit that fiscal year. Forced to close furnaces, the company exhibited a typical Japanese economic aversion to layoffs, opting instead to offer standard early retirement enticements but also less conventional schemes such as a mushroom cultivation venture that used the surplus heat created by steel furnaces to temperature control a fecund fungi complex.

Attributing the drop to higher material costs, the company entered into another troubled year. In 1983, the company reported the end of the fiscal year (March 31) would reveal Nippon Steel was in an even more beleaguered situation. A fall in demand brought about a 39 percent tumble in profits from an already weak previous year. During this time the entire Japanese steel industry struggled in a period of turmoil as other nations such as South Korea, with only a fraction of labor costs, won over business. The company announced a loss in 1986, prompting a determined effort to diversify away from the moribund "smokestack" industrial sector and to provide new work for thousands of employees that would be transferred from closing furnaces.