The 9th "Decarbo Challenge 2026 Spring" Co-creation Business Contest Held, Seriously Aiming for Social Implementation with Decarbonization as its Theme!

Earth hacks Inc. (Headquarters: Shibuya-ku, Tokyo; President and CEO: Sumito Sekine), which operates a consumer co-creation platform aiming to develop decarbonization-related products, services, and businesses based on consumer voices, held the business contest "Decarbo Challenge 2026 Spring" for companies and students to co-create towards the realization of a decarbonized society. The contest took place over five days on March 6 (Friday), 7 (Saturday), 13 (Friday), 14 (Saturday), and 16 (Monday), 2026, at a venue in Tokyo.

This business contest is a social problem-solving type contest where leading Japanese companies, ministries, and local governments aim to create new businesses that contribute to the realization of a "Decarbonization (Decarbo) society" together with current university students from Gen Z. This 9th edition saw the participation of a total of 8 companies: Mitsui O.S.K. Lines, Ltd., TOKYO GX ACTION 2026 Executive Committee, Tokyo Tatemono Co., Ltd., Hakuhodo Inc. / Hakuhodo Gravity Inc., Mitsui & Co., Ltd. (SAF), Mitsui & Co., Ltd. (Branding), UCC Ueshima Coffee Co., Ltd., and Ricoh x Ricoh Black Rams Tokyo.

About Earth hacks "Decarbo Challenge 2026 Spring"

The uniqueness of this business contest lies not only in students proposing ideas for challenges and themes given by each company but also in the five-day dialogue between employees of companies, ministries, and local governments and students, co-creating highly feasible ideas. Starting from the unique ideas of participating Gen Z students, companies, ministries, local governments, students, and Earth hacks, as three parties, devise decarbonization actions and mechanisms that lead to social implementation, which consumers can engage in positively and enjoyably.

As of March 2026, the Decarbo Challenge has been held 16 times, including collaborations with various themes and regions/cities, with over 120 companies and more than 1,400 participants. Numerous ideas aimed at social implementation have been born to date.

Website: https://co.earth-hacks.jp/decachalle/

Award Results Announcement: Judges' Grand Prize goes to "Tokyo Tatemono Team," Students' Grand Prize to "TOKYO GX ACTION 2026 Executive Committee Team," and Judges' Encouragement Award to "Ricoh x Ricoh Black Rams Tokyo"!

On the final day, March 16 (Monday), 8 student teams that passed the preliminary rounds took the stage for the finals and presented to the judges.

After rigorous judging, the "Judges' Grand Prize" was awarded to the Tokyo Tatemono Team!

They proposed "YNK Candle Nights," a project focusing on the "in-between" time after work, with the theme of creating new value in the Yaesu, Nihonbashi, and Kyobashi (YNK) area. The perspective of transforming the YNK area from a "place to work" to a "place to spend time" by leveraging its diverse corporate cluster and open spaces was highly praised as a proposal that leads to both enhanced area value and innovation creation.

"Tokyo Tatemono Team" awarded the Judges' Grand Prize

The "Students' Grand Prize," decided by student votes, was awarded to the TOKYO GX ACTION 2026 Executive Committee Team!

Focusing on the difficulty for young people to "personalize" environmental issues, they proposed a promotion strategy called "TOKYO Honeybee Operation," using honeybees as a hook. Through experiential events in commercial facilities and a point system (Hachi-P), they provided a sense of daily actions contributing to the environment, designing a pathway from short-term participation to medium-to-long-term behavioral change.

"TOKYO GX ACTION 2026 Executive Committee Team" awarded the Students' Grand Prize

Amidst close judging, the "Judges' Encouragement Award," newly established this time, went to the Ricoh x Ricoh Black Rams Tokyo Team!

They proposed "Rams Festival," combining sports and local events, with the theme of realizing an inclusive and sustainable society where people with disabilities can naturally continue to be part of the local community.

"Ricoh x Ricoh Black Rams Tokyo Team" awarded the Judges' Encouragement Award

General Comments from Expert Judges

This year's judges were Tomoharu Gomi (General Manager, New Business Development Office, Sustainability Impact Business Department, Energy Solutions Division, Mitsui & Co., Ltd.), Yusuke Shimizu (Chief Creative Officer, Earth hacks Inc.), Yusuke Nakamura (Editor-in-Chief, Nikkei XTREND, Nikkei BP), and Bubly (Rikako Takeno / CEO, CGO.com LLC).

Each proposal was judged from multiple perspectives, focusing on five criteria: "Impact," "Feasibility," "Customer Perspective," "Uniqueness," and "Will."

Tomoharu Gomi of Mitsui & Co., Ltd. commented as follows in his general remarks:

"A distinctive feature of this Decarbo Challenge was that the discussions extended beyond the initial framework of decarbonization to various social issues, such as the realization of an inclusive society and changes in consumer behavior. The consumer insights and ideas born from the students' unique perspectives are valuable for companies in creating new value, and I truly felt that this program functions as a co-creation platform connecting companies and the next generation. I hope that all participating students will leverage this experience for their future learning and challenges."

Earth hacks will continue to promote understanding of decarbonization among younger generations through the Decarbo Challenge and contribute to the realization of a sustainable society in collaboration with companies, ministries, and local governments.

"Decarbo Challenge 2026 Spring" Event Outline

Dates: March 6 (Friday), 7 (Saturday), 13 (Friday), 14 (Saturday), 16 (Monday), 2026

Organizer: Earth hacks Inc.

Target: University and graduate students scheduled to graduate between 2027 and 2030

・Mitsui O.S.K. Lines, Ltd.

・TOKYO GX ACTION 2026 Executive Committee

・Tokyo Tatemono Co., Ltd.

・Hakuhodo Inc. / Hakuhodo Gravity Inc.

・Mitsui & Co., Ltd. (SAF)

・Mitsui & Co., Ltd. (Branding)

・UCC Ueshima Coffee Co., Ltd.

・Ricoh x Ricoh Black Rams Tokyo

Date and Time: March 16 (Monday), 2026, 13:30-17:45

Venue: Nikkei Hall (1-3-7 Otemachi, Chiyoda-ku)

Tomoharu Gomi (General Manager, New Business Development Office, Sustainability Impact Business Department, Energy Solutions Division, Mitsui & Co., Ltd.)

Yusuke Shimizu (Chief Creative Officer, Earth hacks Inc.)

Yusuke Nakamura (Editor-in-Chief, Nikkei XTREND, Nikkei BP)

Bubly (Rikako Takeno / CEO, CGO.com LLC)

Introduction of Co-creation Themes and Company Representative Comments from Participating Companies (alphabetical order)

1. Mitsui O.S.K. Lines, Ltd.

[Theme] Considering further development and evolution of the shipping industry's "DarWIN Project," which is a B2B business, devise ways to convey it in a manner that interests the general public.

"Efficient operation" in the unfamiliar field of shipping was a difficult theme, but I was impressed by the proposals that employees would not have thought of. Many ideas combined flexible thinking with feasibility and persuasiveness, and I felt there were proposals we would consider implementing. I am grateful for everyone's serious and enthusiastic efforts. (Mr. Ota, Sustainability Strategy Promotion Department)

2. TOKYO GX ACTION 2026 Executive Committee

[Theme] Let's change. The image of "GX," and daily actions.

A new "GX Action" promotion strategy that young people in Tokyo can participate in with excitement.

I was deeply impressed by how each team, in a short time, delved into the issues, considered solutions based on feasibility, and delivered enthusiastic presentations. We will consider utilizing the proposed ideas for future "TOKYO GX ACTION" promotion strategies. (Mr. Kezuka, TOKYO GX ACTION 2026 Executive Committee Secretariat)

3. Tokyo Tatemono Co., Ltd.

[Theme] Propose a sustainable new business plan that can be realized in the Yaesu, Nihonbashi, and Kyobashi (YNK) area, in tie-up with large companies within YNK.

For the challenge of proposing a sustainable new business, we received wonderful proposals filled with passion, involving repeated hypothesis testing to engage various stakeholders, sometimes even conducting surveys and on-site investigations in a gritty manner. We look forward to further accelerating co-creation with students in the YNK (Yaesu, Nihonbashi, Kyobashi) area through this challenge. (Mr. Hamamura, Urban Development Promotion Department)

4. Hakuhodo Inc. / Hakuhodo Gravity Inc.

[Theme] Propose ideas to convert 40% of the closets of university students who regularly purchase ultra-fast fashion and fast fashion into "circular fashion items" within 5 years.

The university students' commitment to a "consumer's perspective" allowed us to glimpse the real relationship with fashion. All proposals were equally interesting, and despite the difficult theme, I sincerely thank everyone for their persistent efforts until the end. (Mr. Tanoue, Executive Vice President, Hakuhodo Gravity)

5. Mitsui & Co., Ltd. (SAF)

[Theme] From the perspective of behavioral change among consumers who use aircraft, propose mechanisms and measures that will lead to the expansion of SAF utilization in Japan.

I presume that the process of researching and analyzing unfamiliar products and proposing measures was extremely difficult. In that context, we received unique proposals from the students' perspective, which provided great stimulation in terms of both content and attitude. We will utilize this learning in our future business promotion. We thank all the students. (Mr. Sato, Mr. Shimazaki, Carbon Solutions Business Department)

6. Mitsui & Co., Ltd. (Branding)

[Theme] Devise a communication strategy that can convey Mitsui & Co.'s initiatives to solve social issues as a business, across industries and regions, in a way that resonates with young generations (university students to new graduates 1-2 years out) as their own concern.

Thank you to each team for engaging in earnest discussions within the limited time. As the judges commented, it was a "difficult theme," and the presentations, based on "perspectives only students can see" and "sharp analysis uncharacteristic of students," were very stimulating. We will consider implementing the proposed ideas in the future. (Mr. Yoshida, Corporate Branding Office, Public Relations Department)

7. UCC Ueshima Coffee Co., Ltd.

[Theme] Devise visuals, copy, and campaign ideas that will help Gen Z understand and empathize with the value (deliciousness, environmental contribution) of hydrogen-roasted coffee.

I was deeply moved by the proposals that, based on the "reality of university students," suggested new values for UCC's hydrogen-roasted coffee, which began mass production and sales in April 2025, values that we ourselves hadn't noticed! We will definitely proceed with considering future implementation. Thank you to all three teams for your hard work. (Mr. Hashimoto, Mr. Susumu, Hydrogen Roasted Coffee PJT)

8. Ricoh x Ricoh Black Rams Tokyo

[Theme] Consider what can be done using Black Rams Tokyo to realize an inclusive and sustainable society where people with disabilities can continue to be part of the community.

Within a highly abstract theme, we gained significant insights from proposals that incorporated primary information through surveys and visits to group homes. We look forward to working together towards implementation, not letting this end here. (Mr. Shirasaki, Club Visionary Officer, Ricoh Black Rams Tokyo)

About the Co-creation Platform "Earth hacks"

"Earth hacks" is a platform that connects consumers, including Gen Z, with companies and local governments.