-20°C Salt Ice 'ROCK B' Supports Approx. 600 High School Rugby Players and Spectators at Hanazono; Achieves Zero Heatstroke Cases with Re-freezing Service

Mix & Match Co., Ltd. (Headquarters: Osaka, Japan; CEO: Shingo Mori) implemented a heatstroke prevention service utilizing its proprietary -20°C salt ice technology, 'ROCK B,' at the 'Osaka High School Rugby Coming Day 2026,' held at Hanazono Rugby Stadium (Higashiosaka, Osaka) on May 4, 2026 (Greenery Day).

The event, which featured joint training and exchanges among multiple high school rugby teams in Osaka, saw a total of approximately 600 participants, including 400 players and 200 spectators. The company set up two ice pack re-freezing stations within the stadium, preparing 500 neck coolers and 1,000 ice packs. Furthermore, they rapidly cooled bottled water and sports drinks provided by sponsors, offering unlimited re-freezing services for seven hours, and concluded the event without any major heatstroke-related incidents.

This initiative aimed to create a cooling environment for the entire venue, ensuring that heatstroke prevention is not left solely to individuals.

In recent years, the number of extremely hot days has been increasing across Japan, making heatstroke prevention in sports settings a critical social issue. A preventive approach—stopping body temperature from rising rather than reacting after symptoms appear—is essential. In sports, rapid cooling is crucial to prevent severe cases. Cooling the neck area is known to reduce physical strain in hot environments, creating a need for infrastructure that allows for continuous cooling.

'ROCK B' is a powdery salt ice made by freezing salt and water at -20°C. It enables rapid re-cooling, which was difficult with conventional ice, allowing for repeated cooling during breaks or waiting times. Because ice packs can be re-frozen in just a few minutes, there is no need for long-term storage, allowing for continuous on-site operation.

Although the maximum temperature around Hanazono Rugby Stadium on the day of the event was around 21°C, participants expressed high expectations, saying, 'It would be reassuring even in mid-summer' and 'It will be even more useful in summer tournaments.' Over 90% of respondents gave the service a high rating in a survey.

Mix & Match Co., Ltd. plans to expand the use of this technology to various hot environments, including school events, outdoor festivals, construction sites, and regional disaster prevention, beyond just sports tournaments. The company is committed to spreading the concept of 'cooling infrastructure' and promoting the re-freezing station model.