High School Players Collapse in Extreme Heat, Yet Venue and Schedule Remain Unchanged: ‘Summer Koshien’ Held Hostage by Adult Interests

Deadly Heat Forces Even Professional Baseball to Halt
Koshien, a Symbol of Youth and Grit, Presses Ahead in Extreme Heat
Calls Mount for Sweeping Changes to Tournament Schedule and Venue

Japan’s premier summer sporting event, the National High School Baseball Championship—widely known as the “Summer Koshien”—faces an existential threat from record-breaking heat. Japan’s average summer temperature last year reached its highest level since records began in 1898, yet this year’s tournament has again brought together 49 high school teams in August, the hottest month of the year. Professional baseball and other high school sports have suspended games, moved into domed stadiums or relocated their competitions, while Koshien continues to adhere to a venue and schedule maintained for more than a century. The repeated collapse of players from heatstroke has prompted discussions over seven-inning games and revised start times, but no fundamental solution appears viable without changing when and where the tournament is held.

Opening Under the Specter of Heatstroke

According to the Japan High School Baseball Federation (JHBF), the 2026 Koshien tournament opened on August 5 in Nishinomiya, Hyogo Prefecture, near Osaka. Jointly organized by the JHBF and The Asahi Shimbun, the tournament features 49 regional representatives from across Japan, with the final scheduled for August 22. Concerns are mounting, however, over staging the competition during the hottest period of the year. The tournament takes its name from Koshien Stadium in Hyogo Prefecture, the home ballpark of the Hanshin Tigers. The area endured persistent temperatures of 35–40 degrees Celsius last summer.

According to the Japan Meteorological Agency, Japan’s average summer temperature in 2025 was 2.36 degrees Celsius above the long-term norm, the highest since records began in 1898. The country’s average summer temperature is rising by 1.38 degrees Celsius per century. With unprecedented heat recurring in 2023, 2024 and 2025, the extreme conditions surrounding the August tournament have moved outside the bounds of a temporary weather anomaly. During last year’s competition, numerous players were unable to continue after suffering exhaustion or dizziness, while others were carried off the field on stretchers. The conditions are especially punishing for high school students who have yet to reach adulthood.

Players and Spectators Under Simultaneous Threat

Warning signs had already emerged during this year’s regional qualifiers. According to The Nikkei, several Chiben Gakuen players displayed symptoms of heatstroke during the third round of the Nara high school baseball tournament in Kashihara on July 20. Chiben Gakuen, the runner-up in the spring invitational tournament, ultimately lost 9–6 after key players, including ace Mahiro Sugimoto, were unable to perform at full strength. The team’s third-base dugout was directly exposed to intense afternoon sunlight. Kazunori Tanaka, manager of Nara University High School, whose team occupied the shaded first-base dugout, said, “The opposing players looked as though they were struggling badly because they remained exposed to the sun even while resting in the dugout.”

The extreme heat engulfs the stands as well as the field. The Alps stands at Koshien Stadium, where school cheering squads congregate, are exposed for extended periods to direct sunlight and radiant heat from scorching seats. Continuous musical performances and chants further elevate body temperatures and increase the risk of dehydration. Spectators also receive none of the scheduled cooling breaks provided to players and tournament personnel. Koshien’s distinctive mass cheering culture has therefore emerged as another safety hazard during extreme heat. Hours of sustained cheering accelerate increases in body temperature and fluid loss, heightening the risk of heat-related illness among spectators.

Table 1. Why the “Summer Koshien” Persists Despite Extreme Heat

No Exit on Either Venue or Schedule

The JHBF, however, has neither changed the tournament schedule nor moved the venue. It has merely introduced more granular heat countermeasures than last year. Institutional constraints remain deeply entrenched. A JHBF official told The Nikkei, “Koshien is used for professional baseball outside the summer, while regional stadiums are already booked for university baseball and other events, leaving us unable to secure a venue.” Changing the symbolic setting of Koshien remains difficult, while altering the schedule poses another formidable challenge.

Japanese baseball also lacks a single organization comparable to a national football association that oversees both professional and amateur competition. Professional, university and high school baseball operate independently, making it difficult to coordinate the entire calendar and shift the high school tournament to another season. School schedules present another obstacle. Holding the competition during summer vacation reduces missed classroom time, and the sequence from regional qualifying tournaments to the national championship is already firmly anchored in the summer months. Moving the tournament would require a wholesale redesign of the existing system encompassing schools, baseball organizations and stadium operators nationwide.

Extreme-Heat Tradition Trapped in a Youth Narrative

A culture that treats the Summer Koshien itself as an enduring ideal has also impeded change. In Japan, Koshien is consumed as a national drama in which young players display grit, endurance, sacrifice and teamwork by persevering under the searing sun. Images of sweat-soaked uniforms, dirt-streaked faces and defeated players collecting Koshien soil through tears have long defined the tournament. The ordeal of competing in oppressive heat has been absorbed into a romanticized vision of youth, fostering a long-standing sentiment that the hotter the conditions, the more authentically Koshien-like the tournament becomes.

Broadcasters and news organizations have reinforced this image. Held over an extended period during summer vacation, Koshien is a vast national media event that binds schools, local communities and alumni together. Moving the competition to a cooler season could erode both the cultural symbolism and commercial appeal of the Summer Koshien. Nationwide broadcasting networks reproduce this sentiment every year. NHK is airing every game of this year’s tournament on television, radio and online, while BS Asahi is broadcasting the entire competition live in 4K from the opening ceremony through the final.

The tournament’s broadcasting power is reflected in the annual ratings for the championship game. Last year’s final featuring Okinawa Shogaku High School recorded an average household audience share of 46.3% in Okinawa, with a peak rating of 52.3%. As games involving regional representatives have evolved into major events mobilizing entire schools, alumni networks and communities, broadcast schedules, online distribution and local cheering culture have all become entrenched around the August calendar. The Asahi Shimbun’s direct participation in both tournament operations and regional qualifying events has further consolidated the midsummer competition into a vast commercial system jointly sustained by the media and local communities.

This rigidity is also embedded in the JHBF’s official documents. In its final report issued last December, the federation defined high school baseball as part of school education and stipulated that the national tournament should be held during summer vacation. Its review of heat countermeasures also proceeded from the premise that the national championship would continue to be staged at Koshien. The JHBF cited the stadium’s status as a byword for high school baseball and the proliferation of the term “Koshien” across a wide range of cultural events as grounds for preserving the venue. The report also endorsed continued use of Koshien based on its century-long history of hosting the national tournament since the stadium opened in 1924 and its broader social symbolism.

Sports Halt and Relocate as Koshien Holds Firm

Tradition and commercial appeal cannot justify pressing ahead with games in dangerous heat. Having formally defined high school baseball as part of school education, the JHBF must place the safety of underage players at the forefront of tournament operations. Games in which players collapse from cramps and exhaustion before being carried away on stretchers cannot credibly be packaged as youth development dramas. Romanticizing endurance under punishing conditions transfers the burden of safety onto the students themselves.

Professional baseball has already responded to the same extreme heat by halting play. The Korea Baseball Organization (KBO) canceled all first- and second-team games on August 5 and 6 after spectators displayed symptoms of heat-related illness during a game in Incheon on August 4. The number of games canceled because of extreme heat this year has risen to 15. In Japan, a minor-league professional baseball game at Lotte Urawa Stadium in Saitama Prefecture was suspended on July 22 after several players developed physical abnormalities. The temperature reached 38.7 degrees Celsius, marking the first official Japanese professional baseball game canceled because of extreme heat. Nippon Professional Baseball (NPB) is also considering rules allowing host clubs to cancel games when temperatures approach 40 degrees Celsius.

Investment in Japanese professional baseball stadiums is also adjusting to climate change. Chiba City, the Chiba Lotte Marines and Aeon Mall are considering a fixed-dome design for a new stadium scheduled for completion by 2034 to replace ZOZO Marine Stadium. An outdoor venue with an estimated cost of approximately $381 million was initially considered the leading option. Mounting concerns over extreme heat and growing demands from the team and local residents prompted planners to shift toward an indoor stadium costing more than $634 million. The revised plan accepts an increase of at least $254 million in construction costs to protect players and spectators while enabling year-round use of the facility.

Japanese high school football has responded by relocating its competitions. Since 2024, the national inter-high school athletic championships have staged the women’s football tournament in Hokkaido and the men’s tournament in Fukushima. The move overturned a long-standing hosting convention to avoid the regions and times of day most severely affected by extreme heat. Relocation imposed significant travel burdens on schools and cheering squads nationwide, yet prioritizing the safety of teenage athletes prompted a fundamental change in tournament operations.

Palliative Measures Fall Short

The JHBF has also introduced countermeasures. This year, it extended the period during which early-round games are divided into morning and afternoon sessions and introduced an eight-minute cooling break after the fifth inning. Ice slurry and oral rehydration solutions are available, while approximately 12 physical therapists have been deployed on site. Yet afternoon games from the third through the 10th day begin at 1:30 p.m., when temperatures typically reach their daily peak. Games are also scheduled for 1 p.m. and 3:30 p.m. on the 11th and 12th days. The federation is measuring the wet-bulb globe temperature (WBGT), an extreme-heat risk indicator incorporating temperature, humidity and solar radiation, to issue warnings. Its publicly announced measures contain no rule requiring games to stop automatically once the reading exceeds a specified threshold.

The seven-inning format under consideration by the JHBF also has clear limitations. A federation review committee estimated that reducing games from nine innings to seven would cut the average duration from approximately two hours to 90 minutes and lower the average pitch count from 130 to 100. The JHBF says the change could reduce players’ exposure to extreme heat by 30 minutes, yet the temperature, humidity and radiant heat on the field would remain unchanged. Pregame practice, waiting periods, travel and cheering-squad activities would also continue regardless of the number of regulation innings. Yoshihiro Gotoura, head of orthopedics at the Kyoto Prefectural Maizuru Children’s Rehabilitation Center, warned, “If temperatures rise further, even seven-inning games could become impossible.”

Converting Koshien Stadium into a domed venue also faces intertwined cost and land constraints. Hanshin Electric Railway, which operates the stadium, says a dome conversion is impractical because construction would have to proceed while the venue continues hosting professional and high school baseball games, while the surrounding site offers little available space. The company is instead spending approximately $95 million to extend a canopy over the Alps stands, where school cheering squads congregate. The project will reduce direct sunlight in the stands, but the playing field will remain exposed to outdoor weather conditions. Calls are consequently growing within Japanese baseball for measures extending far beyond palliatives such as seven-inning games and roof installation. Wataru Sue, manager of Sendai Ikuei Gakuen High School, called for reform without taboos, saying, “The discussion must begin with whether we can change the venue, the timing and the format of the tournament.”