A Plurality Atlas

Who is Haruyuki Seki?

The representative director of Code for Japan and a central figure in Japanese civic tech. Seki is one of the organizers of Plurality Tokyo, introduced Talk to the City to Takahiro Anno, and serves as a board member of Digital Democracy 2030.

Trace the road by which Plurality spread in Japan, and by which "broad listening" came to be used in the 2024 Tokyo governor's election, and one person keeps turning up: someone who has spent more than ten years in Japan on citizens using technology to solve local problems.

In short

Haruyuki Seki (関治之, Hal Seki, @hal_sk) is a person who has spread "civic tech" in Japan: citizens using technology to solve problems in their communities and society [1].

During the Great East Japan Earthquake of 2011, Seki launched the information-sharing site sinsai.info, and in 2013 founded Code for Japan, of which Seki is now the representative director [1]. Seki has close ties with Taiwan's Audrey Tang, and is also one of the organizers of "Plurality Tokyo", the gathering that became a starting point for Plurality's spread in Japan [2].

Connection to Plurality

An organizer of Plurality Tokyo. The book Broad Listening introduces Seki as one of the organizers of Plurality Tokyo [2]. On July 23, 2024, Seki hosted "Plurality Tokyo Meetup with Audrey & Glen", which invited Tang and Glen Weyl [3]. → Plurality in Japan

Introducing Talk to the City to Takahiro Anno. According to the same book, on May 23, 2024, Seki, Takahiro Anno and Hirokazu Nishio met, through Nishio's introduction. At that meeting Seki introduced "Talk to the City" (TTTC), a tool that uses AI to organize and display the opinions of many people. On May 30 Nishio tried TTTC on roughly 20,000 public comments about AI. The next day, May 31, Seki presented the results in a keynote lecture in the session "AI and Democracy" at the annual conference of the Japanese Society for Artificial Intelligence [2]. This led to the broad listening of the 2024 governor's election [2]. → Takahiro Anno's 2024 Tokyo campaign

A three-way conversation with Tang and Weyl. Seki appeared as Japan's leading figure in civic tech in the Cybozu Shiki conversation "新概念『Plurality』を解く" (Unpacking the new concept of Plurality), published in October 2024 (moderated by Nishio) [4].

A dialogue with Tang in Taiwan. On March 22, 2024, Seki met Tang in Taiwan with a delegation from Japan. Seki said: "I feel that Taiwan is kind of the epicenter of the new movement of plurality and also Web3." Tang explained the nearly finished book and how "數位" (digital) can also be read as "plural". Seki mentioned translation into Japanese and events including Plurality Tokyo in July, and invited Tang (CC0 verbatim transcript) [5]. → Shuwei and ⿻

Looking back on Funding the Commons Tokyo 2024. On note, Seki described the panel with Weyl and Tang at this event, and the discussion of broad listening between Anno and Tang. Using Weyl's idea of being "supermodular", Seki explained that the more digital public goods (software and data anyone can use) are used, the more the value of related public goods grows too [6]. → Supermodularity, digital public infrastructure

On the board of Digital Democracy 2030. Seki's name is listed among the board members on the official website of Digital Democracy 2030 (DD2030), together with Ken Suzuki and Makiko Nakamuro [7].

International recognition. On October 6, 2025, Seki received the Charles T. Manatt Democracy Award 2025 from the International Foundation for Electoral Systems (IFES), the first Japanese person to receive it. IFES has made public that Tang nominated Seki [8].

Links with Mitou

In the second half of fiscal 2009, Seki was selected for IPA's Mitou IT (main program) as chief creator of "Development of a mobility management platform using open-source technology" [9].

Main ideas

Civic tech is a culture. On Code for Japan's tenth anniversary, Seki argued on note that civic tech is a "culture" [10]. Code for Japan's vision is a society where we think together and build together [8].

Tools for participatory policymaking, brought to local governments. Code for Japan brought to Japan Decidim, a participatory consensus-building platform born in Barcelona, Spain. It was first introduced in Japan in October 2020 in Kakogawa City, Hyogo Prefecture, where about 200 people, including local high school students, took part in shaping a smart city plan with about 300 comments [11].

In 2022, when Japan came first in the e-Participation category of the United Nations e-government ranking, Seki stressed on note the importance of combining online tools with offline procedures [12].

Introducing Plurality. In slides for a talk at the Japanese Society for Artificial Intelligence on May 31, 2024, Seki explained the three philosophies behind Plurality (one of them being Hannah Arendt's), Decidim, Polis and digital public goods side by side [13]. → Hannah Arendt

The illusion that citizens will solve things on their own. In a note post in October 2025, Seki wrote, from 13 years of experience, that a hope often heard from local government staff, that citizens will take the initiative and solve local problems by themselves, is an "illusion". Seki pointed out that Code for America in the United States was able to get started because it had large funding from foundations [14].

Small experiments in plural futures. On note, Seki reported on "kuu village" in Tsukigase, Nara Prefecture, where about 40 people, including local practitioners, developers and researchers, lived together for a week. Seki described Tang's idea of the "Hyperlocal" as a good fit for it [15].

Further reading

  1. Tang's dialogue with the Japanese delegation (English, verbatim transcript, 2024-03-22, CC0) — https://github.com/audreyt/transcript/blob/main/2024-03-22-Conversation-with-Hal-Seki-and-Japanese-delegates.md
  2. Broad Listening, chapter 4, section 1 "Takahiro Anno's Initiatives in the 2024 Tokyo Governor Election" (in Japanese; English translation in the same repository; CC BY-NC 4.0) — https://github.com/digitaldemocracy2030/broad-listening-book/blob/f69c60c838a91b91668abf109d7093b240610139/en/04_01_takahiro_anno_initiatives.md
  3. Haruyuki Seki's official profile (in Japanese, profile, CC BY-ND 4.0) — https://www.halsk.xyz/
  4. Cybozu Shiki, "新概念『Plurality』を解く" (in Japanese, conversation, 2024-10-03) — https://cybozushiki.cybozu.co.jp/articles/m006211.html
  5. Haruyuki Seki, "シビックテックによる、社会と民主主義のアップデート" (Updating Society and Democracy Through Civic Tech) (in Japanese, talk slides, 2024-05-31) — https://speakerdeck.com/halsk/sibitukutetukuniyoru-she-hui-tomin-zhu-zhu-yi-noatupudeto
  6. Haruyuki Seki, "シビックテックは次のステージへ進めるか" (Can civic tech move on to its next stage?) (in Japanese, essay, 2025-10-10) — https://note.com/hal_sk/n/ne58a76fa25a8

Sources

  1. Haruyuki Seki, official profile (in Japanese) — https://www.halsk.xyz/ ［CC BY-ND 4.0］
  2. Broad Listening, chapter 4, section 1 "Takahiro Anno's Initiatives in the 2024 Tokyo Governor Election" (in Japanese; English translation in the same repository) — https://github.com/digitaldemocracy2030/broad-listening-book/blob/f69c60c838a91b91668abf109d7093b240610139/en/04_01_takahiro_anno_initiatives.md ［CC BY-NC 4.0］
  3. Plurality Tokyo Meetup with Audrey & Glen (YouTube, 2024-07-23) — https://www.youtube.com/watch?v=zP7s_xFVGY8
  4. Cybozu Shiki, "新概念『Plurality』を解く" (2024-10-03, in Japanese) — https://cybozushiki.cybozu.co.jp/articles/m006211.html
  5. Conversation with Hal Seki and Japanese delegates (2024-03-22) — https://github.com/audreyt/transcript/blob/main/2024-03-22-Conversation-with-Hal-Seki-and-Japanese-delegates.md ［CC0］
  6. Haruyuki Seki, "Funding the Commons Tokyo 2024: デジタル公共財が切り拓く、新たな社会への挑戦" (Funding the Commons Tokyo 2024: the challenge of a new society opened up by digital public goods) (note, 2024-08-09, in Japanese) — https://note.com/hal_sk/n/n612ee1ace100
  7. Digital Democracy 2030, "About us" (in Japanese) — https://dd2030.org/about
  8. PR TIMES, "日本人初の受賞：Code for Japan 関治之が『Charles T. Manatt Democracy Award 2025』を受賞" (First Japanese recipient: Code for Japan's Haruyuki Seki receives the Charles T. Manatt Democracy Award 2025) (2025-10-16, in Japanese) — https://prtimes.jp/main/html/rd/p/000000075.000039198.html
  9. IPA, second half of fiscal 2009 Mitou IT (main program) selection results (in Japanese) — https://www.ipa.go.jp/jinzai/mitou/it/2009/2009-2-hontai/koubokekka.html
  10. Haruyuki Seki, "シビックテックとは文化である" (Civic tech is a culture) (note, 2023-12-08, in Japanese) — https://note.com/hal_sk/n/nab06fa3794f8
  11. Haruyuki Seki, "アジャイルガバナンスとシビックテック" (Agile governance and civic tech), slides (2021-07-10, in Japanese) — https://speakerdeck.com/halsk/aziyairugabanansutosibitukutetuku
  12. Haruyuki Seki, "国連電子政府ランキングのeParticipation部門で日本が首位を獲得" (Japan takes first place in the e-Participation category of the UN e-government ranking) (note, 2022-10-04, in Japanese) — https://note.com/hal_sk/n/n9be11f4842a0
  13. Haruyuki Seki, "シビックテックによる、社会と民主主義のアップデート" (2024-05-31, in Japanese) — https://speakerdeck.com/halsk/sibitukutetukuniyoru-she-hui-tomin-zhu-zhu-yi-noatupudeto
  14. Haruyuki Seki, "シビックテックは次のステージへ進めるか──10年の歩みと、これからの課題" (note, 2025-10-10, in Japanese) — https://note.com/hal_sk/n/ne58a76fa25a8
  15. Haruyuki Seki, "kuu villageという実験。共同生活から芽吹く、多元的な未来のかたち" (The kuu village experiment: plural futures sprouting from living together) (note, 2025-10-14, in Japanese) — https://note.com/hal_sk/n/n80033fb51219
Related: What is civic tech? ・ What is the Plurality movement in Japan? ・ What is Digital Democracy 2030 (DD2030)? ・ What is Talk to the City (TTTC)? ・ What is Broad Listening? ・ What was Takahiro Anno's 2024 Tokyo campaign? ・ What is supermodularity? ・ What is digital public infrastructure (DPI)? ・ What is Mitou (the IPA Mitou program)? ・ Who is Audrey Tang? ・ Who is Hirokazu Nishio? ・ Who is Takahiro Anno?

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