Seigi Tanaka is a Japanese professional baseball pitcher for the Hokkaido Nippon-Ham Fighters of Nippon Professional Baseball (NPB). He played the Fukuoka SoftBank Hawks after being drafted in 2016.

The Hokkaido Nippon-Ham Fighters is a Japanese professional baseball team based in Kitahiroshima, Hokkaidō, in the Sapporo metropolitan area. They compete in the Pacific League of Nippon Professional Baseball, playing the majority of their home games at ES CON Field Hokkaido. The Fighters also host a select number of regional home games in cities across Hokkaidō, including Hakodate, Asahikawa, Kushiro, and Obihiro. The team's name comes from its parent organization, Nippon Ham, a major Japanese food-processing company.