⚾ For over a century, baseball has meant nine innings. Now Japan is questioning this fundamental rule for high school games. With 70% of schools opposing the change but heat stroke risks climbing, Japan's beloved Koshien tournament faces its biggest transformation ever. Here's why this debate matters far beyond the baseball diamond.

The Proposal That's Dividing Japan

On December 5, 2025, Japan's High School Baseball Federation (JHBF) received a final report from its special committee recommending that all high school baseball games be shortened from nine innings to seven, starting with the 100th Anniversary Spring Koshien tournament in 2028.

The proposal has ignited fierce debate across Japan. To understand why this seemingly technical rule change has become such a contentious issue, you need to understand what Koshien means to Japanese culture.

Understanding Koshien: More Than Just Baseball

Koshien Stadium, located in Nishinomiya, Hyogo Prefecture, hosts Japan's national high school baseball championships every spring and summer. But calling it merely a sports venue would be like calling the Olympics merely an athletic event.

For Japanese people, Koshien represents purity, dedication, and the fleeting beauty of youth. The summer tournament draws television audiences rivaling major professional sporting events. High school players who reach Koshien become overnight celebrities, their games analyzed and their personal stories shared across the nation.

The atmosphere combines fierce competition with elaborate cheerleading performances, school fight songs, and dramatic storylines of underdogs and favorites. When a team loses, their high school baseball career ends instantly—no second chances, no next season. This "one and done" format creates emotional drama that captivates millions.

Why Consider Shortening Games?

The push for seven-inning games stems from multiple converging challenges:

Extreme Heat Crisis: Summer temperatures at Koshien regularly exceed 35°C (95°F). Despite implementing a two-session daily schedule (morning and evening games) in 2025, the fundamental risk to players remains. Heat-related illnesses have become an increasingly urgent concern as climate change intensifies summer conditions.

Declining Player Numbers: Japan's shrinking youth population has hit high school baseball hard. More schools are forming combined teams due to insufficient players, and smaller rosters face disproportionate physical strain across nine-inning games.

Pitcher Welfare: Modern high school pitchers throw harder than ever—speeds approaching 150 km/h (93 mph) are no longer rare. Combined with traditional Japanese tournament structures that can require pitchers to throw complete games on consecutive days, the injury risk has never been higher.

Global Standard Alignment: Perhaps surprisingly, nine-inning high school baseball is increasingly a Japanese exception. The United States, South Korea, Taiwan, Australia, and many other baseball nations already use seven innings for high school competition. International youth tournaments under the World Baseball Softball Confederation (WBSC) also use seven innings.

The Survey Results: A Nation Divided

The JHBF conducted three separate surveys in 2025, revealing fascinating demographic divides:

General Public Survey (2,472 respondents via professional survey company):

• Support: 35.9%
• Oppose: 25.0%
• Women across all age groups favored the change
• Primary reason for support: Heat stroke prevention

Member Schools Survey (2,643 schools):

• Support: 20.8%
• Oppose: 70.1%
• Schools with 0-20 players showed higher support (28.2%)
• Schools with 61-80 players: 91.1% opposed
• Primary reason for opposition: Reduced playing opportunities

Open Website Survey (8,953 respondents):

• Support: 768
• Oppose: 7,923
• Nearly 90% opposed

The stark contrast between general public opinion and those directly involved in high school baseball reveals a fundamental tension: outsiders prioritize safety while insiders prioritize tradition and playing time.

Arguments For the Change

Proponents of seven-inning games make several compelling points:

Player Safety First: Reducing game length directly reduces heat exposure. The seventh and eighth innings are when fatigue-related injuries and heat illness spike.

Protecting Young Arms: Fewer innings mean fewer pitches, protecting developing shoulders and elbows. With players throwing harder than previous generations, this protection becomes more critical.

Leveling the Playing Field: Powerhouse schools with 60+ players can easily rotate fresh pitchers. Schools with only 11-15 players must rely on one or two arms. Shorter games reduce this competitive disadvantage.

Operational Efficiency: Shorter games allow more flexible scheduling, reduced facility costs, and less burden on volunteer coaches who balance teaching duties with baseball responsibilities.

Following Successful Models: The WBSC U-18 World Cup, held in Okinawa in September 2025, used seven-inning games. Japan won the tournament, proving competitive baseball can thrive under shortened rules.

Arguments Against

Opposition to the proposal comes from passionate voices within baseball:

Destroying Late-Game Drama: The emotional heart of high school baseball often beats in the eighth and ninth innings. Come-from-behind victories in the final frame are legendary moments in Koshien history. Seven-inning games eliminate these possibilities.

Breaking Historical Continuity: Over a century of records and statistics were compiled under nine-inning rules. Comparing achievements across different era becomes problematic, potentially diminishing the significance of both old and new accomplishments.

Creating Transition Problems: University, semi-professional, and professional baseball all use nine innings. A sudden jump from seven to nine innings could disadvantage Japanese players compared to international peers who competed at nine innings throughout their development.

Takashi Kajishaba, a respected former high school coach, argues: "Before considering seven innings, there's much more we should do first—implement mercy rules at Koshien, adopt the designated hitter to reduce pitcher fatigue. Seven innings shouldn't be the first solution we try."

The Koshien Dilemma

Critics often ask: "Why not just move the summer tournament to a cooler month, or use a domed stadium?"

The answer involves complex realities about Japanese high school baseball economics:

• The JHBF doesn't pay rental fees for Koshien Stadium, using it through Hanshin Electric Railway's goodwill
• Domed alternatives like Kyocera Dome would require rental fees the federation cannot afford
• Moving the tournament date would conflict with the school academic calendar and other regional competitions
• The tournament's newspaper co-sponsors (Asahi and Mainichi) face their own financial constraints as print media declines

The special committee's report explicitly states that continuing to hold national tournaments at Koshien is "desirable from historical and social perspectives." Seven-inning games represent an achievable compromise within these constraints.

A Test Run at the 2025 National Sports Festival

In October 2025, the National Sports Festival baseball competition in Shiga Prefecture became the first official high school tournament in Japan to use seven-inning rules.

Results were mixed. Over 60% of participating teams reported the change felt "unsatisfying" for both players and supporters. However, tournament operations proceeded smoothly, with shorter games allowing more efficient scheduling—a practical benefit for multi-team competitions.

What Happens Next?

The JHBF declined to make a final decision at its December 2025 meeting, opting for continued deliberation. Chairman Takara stated the organization would "continue discussing the report's contents in future board meetings."

This cautious approach reflects the genuine difficulty of the decision. Forcing through unpopular changes risks alienating the baseball community. Yet delays in heat protection measures put young athletes at continued risk.

The committee's report emphasizes that successful implementation requires "widely communicating the intentions and effectiveness of seven-inning games." Building understanding and support may be as important as the rule change itself.

A Crossroads for Japanese Baseball

Japanese high school baseball stands at a historic crossroads. For over a century, it has operated under the same fundamental rules while becoming an integral part of Japanese cultural identity.

Now, facing climate change, demographic shifts, and evolving understanding of youth athlete welfare, the institution must decide: How much change is acceptable to preserve what matters most?

The answer will shape not just high school baseball but how Japan approaches the tension between tradition and adaptation—a question that resonates far beyond the baseball diamond.

What about in your country? How do youth sports balance tradition with athlete safety? Do high school or secondary school baseball games in your region use nine innings, seven, or some other format? We'd love to hear how different cultures approach these questions.

References

• https://www.jhbf.or.jp/topics/info/251205_2.html
• https://www.jhbf.or.jp/questionary/
• https://www.nikkei.com/article/DGXZQOKC05A2O0V01C25A2000000/
• https://www.hb-nippon.com/articles/3238
• https://toyokeizai.net/articles/-/931579
• https://sportie.com/2022/11/high-school-sports-20
• https://number.bunshun.jp/articles/-/868729