1973 Nippon Professional Baseball season

The 1973 Nippon Professional Baseball season was the 24th season of operation of Nippon Professional Baseball (NPB). This was the first season with a playoff system, albeit only in the Pacific League, which would match the first-place teams of the first half and second half of the season; if a team finished first place in both halves of the season, they automatically were the champion of the league and therefore went on to play in the Japan Series. On July 11, 1973, a 9-8 victory by the Nittaku Flyers over the Lotte Orions meant that the Nankai Hawks won the inaugural first-half championship. On July 27, the second half began for the Pacific League. On October 5, the Hankyu Braves clinched the second-half in the Pacific when the Lotte Orions lost to the Taiheiyo Lions that would set up a Braves-Hawks playoff series starting on October 19. Meanwhile, the Central League went down to the wire, with the Hanshin Tigers leading with two games remaining before the Tigers hit a lull as the Yomiuri Giants rallied to win the pennant again with a 9-0 victory on October 22 over the Tigers.

This system would continue until 1982.