Tennis Bear is a digital sports platform that brings recreational players together in Japan, starting with tennis.


Tennis is growing in popularity in Japan, however, there are still barriers to casual play. These barriers include high occupancy of local courts and no digital scheduling programs. Recreational players find it challenging to play tennis whenever and wherever they want. The challenge is to simultaneously develop both the supply side (tennis court providers on antiquated booking systems) and demand side (tennis players, coaches, etc).


Tennis Bear enables casual players to find and reserve a local court through a rich digital experience. Tennis court operators benefit from wider visibility of their respective courts and insights from player behavioral data. Tennis Bear's two-sided marketplace has the potential to create network effects (tournaments, player communities, etc.) that can be repeatable across other sports such as basketball, soccer, etc.

Why Two Founders are Building a Community-first Platform for Sports Enthusiasts

Words by Kyra Yamamoto

The relationship between Tennis Bear and Moon is not so much of a venture company and incubator, but more as colleagues who have been running fast and growing together. In fact, Tennis Bear started in 2016 before Moon had even launched. Hiroyuki Mashihara was working as an engineer at NTT DATA when he personally experienced difficulties booking tennis courts around Tokyo. Kei Esaki, who was working for Mitsui & Co. on infrastructure projects at the time, wanted to help Hiroyuki tackle this problem too.

After applying for Mitsui's in-house entrepreneurship program, the two joined the newly developed Moon Creative Lab in early September 2019. From the very beginning, Tennis Bear aimed to provide a service that helps users not only locate and reserve tennis courts, but also discover new friends through it.

"The core of the service hasn't changed much between before and after joining Moon," said Kei. "Through the user insights and discussions with designers that I had after joining Moon, I was able to come up with a lot of different ideas for the app, especially for features that would help users connect to each other. While at Moon, I realized the importance of communication, which can be said to be the root of fun in any sport.”

The Tennis Bear team launched their app in January 2020 with only the minimum functionality required. “I remember in 2020, we were constantly expanding the functionality of the app, and at times, we were updating it almost every week,” said Kei. While the team was expanding the functionality of the app, they were also actively launching events organized by tennis court providers to grow the tennis community. The team used blogs, YouTube, and Twitter to provide their community useful information and advice around tennis which earned them positive recognition from fans.

These grass-root activities have led Tennis Bear to positive results. In the last fiscal year which ended in March 2020, the number of monthly active users tripled from 30,000 to 100,000. In addition, the number of users participating in events has increased from less than 100 when they first launched, to over 5,000 users per month. Tennis Bear has steadily evolved to help its users not only find a place to play tennis, but also give them more ways to enjoy their experience.

“This revitalization of the community has improved the loyalty and retention of our users, and we can now expect to attract more customers when we plan events through Tennis Bear, and the revenue from these events is starting to increase over time."

In the future, Tennis Bear will continue expanding its services along the vertical axis of location, player matching and tools, but also include the horizontal axis by introducing new sports including futsal, basketball, and baseball.

“From the beginning, we envisioned expanding our service from tennis to other sports such as futsal, basketball, and baseball. In fact, we've already launched a test website for futsal.”

As for being one of Moon’s more mature ventures, Kei says, "I've shared with other EIRs what we've learned so far, mainly what we've failed to do along the way. I like to share what we've done wrong. I think that's the case for most ventures. They try out different approaches through trial and error, and most of them end up failing. I think I can contribute to Moon by making sure that other ventures don't repeat these same mistakes.”

“I like to share what we’ve done wrong. I think that’s the case for most ventures. They try out different approaches through trial and error, and most of them end up failing. I think I can contribute to Moon by making sure that other ventures don’t repeat these same mistakes.”


Kei Esaki Infrastructure Development Mitsui & Co., Ltd. NTT DATA

Hiroyuki Mashihara Infrastructure Development Mitsui & Co., Ltd. NTT DATA

Moon Team:

Asami Kawanishi Ryo Sugimoto

Executive Sponsor:

Jeremy Clark

Where Tennis Bear is today:

As a maturing venture, Tennis Bear is now focused on steady growth and profit improvement, so controlling burn rate has become a key skill and focus. Outdoor exercise has thrived during the long-running State of Emergency in Japan, and the service continues to acquire new users and court partners and improve both Monthly Active User and retention rates. Moon hopes to spin Tennis Bear out as an independent company in the coming weeks.


Download Tennis Bear on iOS



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