is a professional baseball league and the highest level of baseball in Japan. Locally, it is often called , meaning simply Professional Baseball; outside of Japan, NPB is often referred to as "Japanese baseball".
The roots of the league can be traced back to the formation of the in 1934. The first professional circuit for the sport in Japan, the Japanese Baseball League (JBL), was founded two years later and continued to play even through the final years of World War II. The organization that is today's NPB was formed when the JBL reorganized in 1950, dividing its 15 teams into two leagues, which would meet in the annual season-ending Japan Series championship playoff series of games starting that year.
NPB consists of twelve teams divided equally in two leagues, the Central League and the Pacific League, a format which it has largely kept since . It has seen several waves of expansion and contraction, sometimes at the same time, to keep it at those numbers; most recently, in 2005, the Osaka Kintetsu Buffaloes merged with the Orix BlueWave to form the Orix Buffaloes, while the Rakuten Golden Eagles were added as an expansion team. As is common in Asian baseball (and unlike North American leagues), teams are generally named after their corporate owners, such as Yomiuri and Softbank. NPB also oversees two affiliated minor leagues, the Western League and the Eastern League.
Since the first Japan Series in , the Yomiuri Giants have the most championships with 22, and the most appearances with 37. Following the 2025 season, the Fukuoka SoftBank Hawks, who defeated the Hanshin Tigers 4–1 in the 2025 Japan Series, are the reigning champions. The Japan Series has been contested 76 times as of 2025, with the series tied between leagues with 38 wins apiece.
NPB was the only professional sports league in Japan until the foundation of the J.League in 1993. It is the eleventh-wealthiest professional sport league by revenue in the world, and the second-wealthiest baseball league, behind Major League Baseball (MLB); it is also the wealthiest sports league in Asia. NPB has the second-highest total season attendance of any league, also behind MLB, despite playing considerably fewer games per season.
League structure Nippon Professional Baseball consists of two leagues, the Central League and the Pacific League, which each have six teams. There are also two secondary-level professional minor leagues, the Eastern League and the Western League, that play shorter schedules for developing players in the so called "Farm System". NPB teams are allowed to have more than one minor league team as long as those others are outside of the established farm/minor league system, with the Fukuoka SoftBank Hawks and Yomiuri Giants being the only teams taking advantage of this. As of 2023, the Hawks have three minor league teams, the Giants have two, and the other ten teams only have one minor league team each. Teams below the Eastern and Western Leagues play exhibition matches against various teams of collegiate, industrial, Shikoku Island League Plus, and other NPB minor league statuses.
The Central League and Pacific League operate as separate entities, unlike the four major professional sports leagues of North America and the KBO League in South Korea, whose leagues each operate as one singular entity. As a result, the TV rights for games are always held by a game's home team, except for Japan Series and All-Star Games, which the league owns the rights in a special collaborative system among the 12 teams in order to avoid blackout issues. The Pacific League has used the designated hitter (DH) rule since 1975, while the Central League plans to introduce DH from 2027 season, before it, the Central League has not used the DH outside of interleague play where a Pacific League team is the home team and in the 1985 and 2020 Japan Series.
The season starts in late March or early April, and ends in October, with two or three all-star games in July. In recent decades prior to 2007, the two leagues each scheduled between 130 and 140 regular season games, with the 146 games played by the Central League in 2005 and 2006 being the only exception. Both leagues have since adopted 143-game seasons, 71 or 72 each at home and on road, facing their five respective intra-league opponents 25 times each and facing their six interleague opponents three times each in late May to early June in interleague play, with a separate champion being crowned for the team with the best record through the 18 games of interleague play. In general, Japanese teams play six games a week, with every Monday off (except on specific occasions, such as a game being played outside of the home team's primary stadium or if a rainout forced a game to be postponed to a Monday).Waldstein, David. "Ace Favors Fewer Starts to Protect Pitchers' Arms: Rangers' Yu Darvish Pushes for a Six-Man Pitching Rotation" , New York Times (July 21, 2014). Unlike in Major League Baseball and in KBO League, doubleheaders have not been featured in NPB since the late 1990s.
Following the conclusion of each regular season, the top three teams from each league go on to play in the Climax Series playoff tournament, with the winner of each playoff tournament facing off in a best-of-seven championship series known as the Japan Series (also known as the Nippon Series). Implemented in by the Pacific League (then known as the Pacific League Playoffs) and in by the Central League, the Climax Series is a two-stage system; in the "first stage", the second and third-place ranking teams face off in a best-of-three series played entirely in the second place team's home stadium. In the case of an instance where the series ends 1–1–1, the higher seed always advances to the final stage. In the "final stage", the winner of the first stage will face off against the league's pennant winner in a best-of-six series played entirely in the pennant winner's home stadium. The higher seed always starts with a "ghost win", or a 1–0 advantage in the series before any games have been played, meaning the higher seed only has to win three games whereas the lower seed has to win four games. In the event of a tie, the higher seed would subsequently only need to win two games. The winners of each league's final stage then face off in the Japan Series, a best-of-seven series mirroring the format of the World Series. In the rare instance where the series ends 3–3–1 after seven games, a Game 8 will be played with unlimited innings at the stadium with home-field advantage. Hypothetically, a Japan Series can go up to 14 games in length if each of the first seven games resulted in a 12-inning tie. Since its inception, home-field advantage alternates from year to year between the CL and PL, with the CL representative getting home-field advantage in even years and the PL representative getting home-field advantage in odd years.
Since its adoption by both leagues in 2007, Climax Series does not determine who won each league's pennant, rather the team with the best regular season record in each league wins the pennant, regardless of their result in the Climax Series. This has led to five occasions where the Japan Series champion did not win their league's pennant that year, with those being the Chunichi Dragons, Chiba Lotte Marines, the - Fukuoka SoftBank Hawks and the Yokohama DeNA BayStars. However, from to , the winner of the Pacific League Playoffs was given the Pacific League pennant for that year.
Financial problems Financial problems plague many teams in the league. It is believed that all teams are operating with considerable subsidies, often as much as ¥6 billion (about US$44.9 million), from their parent companies. A raise in the salaries of players is often blamed, but from the start of the professional league, parent companies paid the difference as an advertisement. Most teams have never tried to improve their finances through constructive marketing. In addition, teams in the Central League historically saw much higher profits than the Pacific League, having popular teams such as the Giants and Tigers.
The number of metropolitan areas represented in the league increased from four to five in 1988, when the Nankai Hawks (now Fukuoka SoftBank Hawks) were sold to Daiei and moved to Fukuoka, nine years after the Nishitetsu Lions moved from Fukuoka to Tokorozawa to become the Seibu Lions, and from five to seven between 2003 and 2005, as the Nippon-Ham Fighters moved from Tokyo to Sapporo prior to the season. The Osaka Kintetsu Buffaloes merged with the Orix BlueWave (becoming the Orix Buffaloes) in the middle of 2004, which caused a player strike that eventually resulted in the creation of the Tōhoku Rakuten Golden Eagles being founded in Sendai to maintain the 12-team balance before the season.
Until 1993, baseball was the only team sport played professionally in Japan. In that year, the J.League professional association football league was founded. The new league placed teams in prefectural capitals around the country—rather than clustering them in and around Tokyo—and the teams were named after their locations rather than after corporate sponsors, despite many clubs in the J.League still being owned and subsidized by corporate entities.
The wave of players moving to Major League Baseball, which began with Hideo Nomo, with the help of agent Don Nomura, exploiting a loophole, "retiring" from the Kintetsu Buffaloes, then signing with the Los Angeles Dodgers, has also added to the financial problems. Attendance suffered as teams lost their most marketable players, while TV ratings declined as viewers tuned into broadcasts of Major League games. To discourage players from leaving to play in North America, or to at least compensate teams that lose players, Japanese baseball and MLB agreed on a posting system for players under contract. MLB teams wishing to negotiate with a player submit bids for a "posting fee", which the winning MLB team would pay the Japanese team if the player signs with the MLB team. Free agents are not subject to the posting system, however, and some teams almost never post their players.
History
Origins The first professional baseball team in Japan with later ties to NPB was founded by media mogul Matsutarō Shōriki in late 1934 and called the Dai Nippon Tokyo Yakyu Kurabu ("the Great Japan Tokyo Baseball Club"). After matching up with a team of visiting American All-Stars that included Babe Ruth, Jimmie Foxx, Lou Gehrig, and Charlie Gehringer, the team spent the 1935 season barnstorming in the U.S., winning 93 of 102 games against semi-pro and Pacific Coast League teams. According to historian Joseph Reaves, "The only minor drawbacks to the team's popularity in the States were their kanji characters and their cumbersome Japanese name. They rectified both by renaming themselves the Tokyo Kyojin ['Tokyo Giants'] and adopting a uniform identical to the New York Giants..."Reaves, Joseph A. Taking in a Game: A History of Baseball in Asia (U. of Nebraska Press, 2002), p. 77.
From 1936 to 1950, professional baseball in Japan was played under the banner of the Japanese Baseball League (JBL). The league's dominant team during this period was the Tokyo Kyojin, which won nine league championships, including six in a row from 1938 to 1943 (The team was officially renamed the Yomiuri Giants in 1947).
NPB establishment After the 1949 season, the JBL team owners reorganized into the NPB; Daiei Stars owner Masaichi Nagata promoted a two-league system, which became the Pacific League (initially called the Taiheiyo Baseball Union) and the Central League, with Nagata becoming the first president of the Pacific League. The league now known as Nippon Professional Baseball began play in 1950.