27 Million Fans and Player-by-Player Chants: How Japanese Pro Baseball Runs on Oshi-Katsu
Come to think of it, pro baseball fans were doing oshi-katsu decades before the word existed.
They wear their team’s jersey, sing the cheer songs (calls), and go on ensei, traveling to the genba of home and away games. This article digs into the fan culture of pro baseball, arguably Japan’s oldest form of oshi-katsu, with the latest data.
Background to this article: In April 2025, The Oshi Lab analyzed how pro baseball, the J.League and the B.League have taken on oshi-katsu in Episode 4 of our podcast and the note article “The Surprising Tricks That Turn Sports Fans Into Your Oshi” (in Japanese). This article updates that material with the latest 2026 data (including the record attendance of the 2025 season).
The Data: A Record 27 Million in 2025
According to an official announcement from NPB, Nippon Professional Baseball (in Japanese), attendance at regular-season games in the Central and Pacific Leagues in 2025 was about 27 million, a new record.
- 27M
- Regular-season attendance, a new record
- 12
- Teams pursuing oshi-katsu strategies
Sources: NPB official announcement (attendance, in Japanese); Shueisha Online (team strategies, in Japanese)
Terrestrial TV coverage has long been said to be shrinking, yet ballparks are fuller than ever. No number speaks more eloquently for the shift of weight from “watching” to “taking part.”
There is also an argument (in Japanese) that attendance is growing even though the fan population itself is shrinking. So each fan goes to the ballpark more often and more deeply, which is exactly the consumption structure of oshi-katsu.
An analysis article from Shueisha Online (in Japanese) also names the oshi-katsu strategies of the 12 teams, such as “pair-oshi” talk events, two-shot photos with players, and giveaways for the first women through the gates, as a factor that pushed even teams that missed the title to record attendance. Team official stores now keep a permanent “oshi-katsu goods” category. Pro baseball’s business model has quietly been rewritten, from an age of reaching the masses through broadcasts to an age of letting fans meet their oshi at the genba.
Pro Baseball Has Every Prototype of Oshi-Katsu
| Pro baseball culture | How oshi-katsu says it |
|---|---|
| Cheer songs and chance themes | The source of calls and otagei (idol-fan dance cheers) |
| Independent fan groups | The self-governing body of a fandom |
| Away-game trips | Ensei and sansen (attending a show) |
| Jerseys and towels of your favorite team | Oshi color goods |
| Player acrylic stands and player-produced goods | Acrylic stand and bonus item culture |
| Player birthday campaigns and commemorative goods | Seitansai (birthday celebrations) |
| Three generations supporting the same team | Hako-oshi across generations |
Baseball fans
- A dedicated cheer song for each player
- Independent fan groups with trumpets and drums
- Player birthday campaigns
Oshi-katsu
- Calls for each member
- Self-governing fandoms
- Seitansai birthday celebrations
Pro baseball ran these prototypes for decades before oshi-katsu had a name.
The cheer song culture deserves special mention. Many players have a dedicated cheer song, the whole stand has memorized the lyrics, and a full-throated chorus erupts at every at-bat. Running a culture of “a dedicated call for each oshi” for decades is something almost only pro baseball has done among the world’s sports. The independent fan group style built around trumpets and drums is said to have spread from the 1970s, and became one of the sources of call culture in Japanese entertainment genba.
Case Study: The Nippon-Ham Fighters’ “Oshi Player” Strategy
A frequently cited success story of the oshi-katsu shift is the Hokkaido Nippon-Ham Fighters, a Pacific League team based in Hokkaido, Japan’s northern island. According to Nikkei’s reporting (in Japanese), the team introduced a web service that recommends a compatible player after you answer a few simple questions, and expanded the range of individual player goods. It created a path for hako-oshi fans to find an “oshi player,” and in 2025 passed 1 million in home-game attendance at the fastest pace since moving to ES CON Field.
- 01Meet the wholeThe team and the ballpark experience
- 02Answer a few questionsA web service recommends a player
- 03Find your oshi playerIndividual goods deepen the bond
The team designs the natural shift from hako-oshi to tan-oshi.
What stands out is the order. First they meet you through the whole (the team and the ballpark experience), and then deepen it through the individual (the oshi player). In oshi-katsu terms, the team is designing the natural shift from hako-oshi to tan-oshi. The deeper the fans’ enthusiasm, the more often they visit and the more they spend per item. The team is recreating, with data and services, the fan-development staircase the idol industry has polished.
Hokkaido Ballpark F Village, including ES CON Field, is itself designed with hot springs, saunas, dining and lodging as a seichi (pilgrimage site) that’s fun even if you don’t watch baseball, layering a stay experience on top of the content that is the game.
The 2020s Shift: From “Oshi Team” to “Oshi Player”
What symbolizes pro baseball’s recent oshi-katsu-ization is goods offered player by player. Player acrylic stands, photo cards and birthday commemorative goods: where “individual oshi” was once served by little more than a numbered jersey, it is now segmented as finely as in the idol world.
The presence of women fans has also become fully established since the “Carp Joshi” (Carp girls) boom of the 2010s. Each team now offers women-focused event days and designed goods as standard, and pro baseball is running at the standard of an age when people who “have an oshi” have passed 40% of the population.
And in 2026, the “encounter design” of sports x IP arrived in earnest in pro baseball. Pokémon announced “Pokémon Baseball Festa 2026,” assigning a partner Pokémon to each of the 12 teams, in February and rolled it out at the ballparks. In July a collab with 60 J.League clubs was announced as well, and the technique of handing out “encounters with an oshi” through club x character pairings spread from baseball to soccer (covered in Podcast Episode 59).
Notes From The Oshi Lab: Turning Casual Fans Into Experience, Turning Core Fans Into Oshi-Katsu
We see pro baseball’s record 2025 attendance as the result of two things moving forward at once: “turning casual fans into an experience” and “turning core fans into oshi-katsu.” Welcome first-time families at the ballpark, help them find an oshi player through a compatibility quiz, then deepen it with individual goods and birthday campaigns. A staircase from the entrance to the deep end is being built out across all 12 teams.
What to watch for is leaning too far on the core fans. A design that raises each fan’s spending looks efficient, but it brings the same kind of exhaustion as oshi-katsu fatigue. To make the most of pro baseball’s biggest asset, the fact that you can support a team across generations, ballpark design that has a place for both “people who love deeply” and “people who love lightly” should decide the next ten years.
For inquiries about oshi-katsu measures for teams and sports organizations, contact KAZAORI Inc. (in Japanese).
Related Articles
The J.League and Oshi-Katsu / The B.League and Oshi-Katsu / What Is Oshi-Katsu Marketing? / The Oshi-Katsu Market Size (2026 Edition)
FAQ
How large is pro baseball attendance?
According to NPB's official announcement (in Japanese), attendance at Central and Pacific League regular-season games in 2025 reached about 27 million, a new record. That works out to more than 30,000 per game on average.
Does watching baseball count as oshi-katsu?
Yes. Wearing your favorite team's jersey, singing cheer songs, and traveling to ballparks is oshi-katsu itself. The "oshi player" culture of supporting an individual player has also grown more visible each year with the spread of merch and social media.
How do you find an oshi player?
The way in is open: hometown, position, playing style, or the personality that comes through in a hero interview. Teams are also adding compatibility-quiz services and individual player goods, and the usual path is to start with hako-oshi (supporting the whole team) and find an oshi player from there.
