Daisuke Matsuzaka is a Japanese former professional baseball pitcher, who pitched professionally for 23 seasons, 16 of them in NPB, 7 in MLB. He is currently a baseball color commentator, critic, reporter, and YouTuber. Daisuke is nicknamed "the Monster of the Heisei Era" in Japan and "Dice-K" in the United States by The Boston Globe and USA Today. He played for the Boston Red Sox and New York Mets of Major League Baseball (MLB) and the Saitama Seibu Lions, Fukuoka SoftBank Hawks and Chunichi Dragons of Nippon Professional Baseball (NPB).

The Saitama Seibu Lions are a professional baseball team in Japan's Pacific League based north of Tokyo in Tokorozawa, Saitama Prefecture. Before 1979, they were based in Fukuoka, Fukuoka Prefecture in Kyushu. The team is owned by a subsidiary of Seibu Railway, which in turn is owned by the Seibu Holdings. The team experienced a recent period of financial difficulty, but the situation brightened when the team received a record ¥6 billion posting fee from the Boston Red Sox for the right to negotiate a contract with Daisuke Matsuzaka. Between 1978 and 2008, the team logo and mascot were based on the adult version of Kimba the White Lion, a classic Japanese anime and manga series by Osamu Tezuka. In 2004, former Seibu Lions player Kazuo Matsui became the first Japanese infielder to play in Major League Baseball.