Mita 2-15-45, Minato-ku, Tokyo 108-8345, Japan
sakai<at>sakaioffice<dot>co
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Toyotaka Sakai
Professor of Economics, Keio University
CEO, Toyotaka Sakai Office LLC
Board member, Prudential Life Insurance of Japan
Ph.D. in Economics, University of Rochester, 2005
Toyotaka Sakai is a leading expert in the design of rating algorithms, group decision making, and auction rules. He founded Toyotaka Sakai Office LLC and Economics Design Inc., economics-based consulting firms. He is also a board member at Prudential Life Insurance of Japan. He has participated in several crypto projects as an angel investor/advisor including Astar Network, Chainsight, Gaudiy, ONGAESHI, and Startale.
Toyotaka has written many books for the general public, as well as academic papers. He has worked to promote mechanism design in various media since this field was unknown in Japan.
One of his books, "Doubting Majority Rule" (Iwanami Shoten), is included in a high school Japanese language textbook and has been used in many entrance examinations, including those of Kyoto University and the Metropolitan Police Department. His books have been translated nine times into foreign languages. He has served as a book reviewer for the Yomiuri Shimbun and the Asahi Shimbun for two years each.
His mission is not only to produce academic knowledge, but also to produce the entire process by which it is used by the public.
Co-founder, Economics Design Inc.
Director, Prudential Life Insurance of Japan
Chief Ecoomist, Due dilligence & Deals co.
Advisor in Economic Design, Gaudiy Inc.
Economic Advisor, Chainshght, HorizonX
Economic Asdvisor, ONGAESHI project, Institution for a Global Society
Papers, patents, books
Papers (in English)
Sakai, T. (2025) "The Probability Smoothing Problem: Characterizations of the Laplace Method,” forthcoming in Mathematical Social Sciences
Bochet, O, Sakai, T., and Thomson, W. (2024) “Preference manipulations lead to the uniform rule,” forthcoming in Journal of Economic Theory
Masuda, R. Mikami, S., Sakai, T., Serizawa, and T. Wakayama (2022) “The net effect of advice on strategy-proof mechanisms: an experiment for the Vickrey auction,” Experimental Economics
Okamoto, N. and Sakai, T. (2019) “The Borda rule and the pairwise-majority-loser revisited,” Review of Economic Design
Sakai, T. (2017) “Considering collective choice: The Route 328 problem in Kodaira City,” Japanese Economic Review
Sakai, T. (2016) “Limit representations of intergenerational equity,” Social Choice and Welfare
Sakai, T. (2015) “A search for the general will in a spatial model,” Japanese Economic Review
Sakai, T. (2013) “Axiomatizations of second price auctions with a reserve price,” International Journal of Economic Theory
Sakai, T. (2013) “An equity characterization of second price auctions when preferences may not be quasilinear,” Review of Economic Design
Sakai, T. (2012) “Fair waste pricing: an axiomatic analysis to the NIMBY problem,” Economic Theory
Sakai, T. and Wakayama, T. (2012) “Strategy-proofness, tops-only, and the uniform rule,” Theory and Decision
Sakai, T. (2011) “A note on strategy-proofness from the doctor side in matching with contracts,” Review of Economic Design
Sakai, T. (2010) “A characterization and an impossibility of finite length anonymity for infinite generations,” Journal of Mathematical Economics
Sakai, T. (2010) “Intergenerational equity and an explicit construction of welfare criteria,” Social Choice and Welfare
Bochet, O. and Sakai, T. (2010) “Secure implementation in allotment economies,” Games and Economic Behavior
Hayashi, T. and Sakai, T. (2009) “Nash implementation of competitive equilibria in the job-matching market,” International Journal of Game Theory
Fujinaka, Y. and Sakai, T. (2009) “The positive consequence of strategic manipulation in indivisible good allocation,” International Journal of Game Theory
Sakai, T. (2009) “Walrasian social orderings in exchange economies,” Journal of Mathematical Economics
Sakai, T. (2008) “Second price auctions on general preference domains: two characterizations,” Economic Theory
Fujinaka, Y. and Sakai, T. (2007) “The manipulability of fair solutions in allocation of an indivisible object with money,” Journal of Public Economic Theory
Sakai, T. (2007) “Fairness and implementability in allocation of indivisible objects with monetary compensations,” Journal of Mathematical Economics
Fujinaka, Y. and Sakai, T. (2007) “Maskin monotonicity in economies with indivisible goods and money,” Economics Letters
Bochet, T. and Sakai, T. (2007) “Strategic manipulations of multi-valued solutions in economies with indivisibilities,” Mathematical Social Sciences
Ju, B.-G., Miyagawa, E., and Sakai, T. (2007) “Non-manipulable division rules in claim problems and generalizations,” Journal of Economic Theory
Sakai, T. (2006) “Equitable intergenerational preferences on restricted domains,” Social Choice and Welfare
Sakai, T. and Shimoji, S. (2006) “Dichotomous preferences and the possibility of Arrovian social choice,” Social Choice and Welfare
Sakai, T. (2003) “Intergenerational preferences and sensitivity to the present,” Economics Bulletin
Sakai, T. (2003) “An axiomatic approach to intergenerational equity,” Social Choice and Welfare
Patents (in Japanese)
１【特許番号】特許第7177901号(P7177901)
【発明の名称】「マッチング装置、マッチング方法、およびマッチングプログラム」
【特許権者】損害保険ジャパン株式会社、株式会社エコノミクスデザイン、株式会社ＷＡＮＤ
【発明者】金崎 寛、坂井 豊貴、岡本 実哲、丹下 靖英、大竹 康弘、加内 慎也
２【特許番号】特許第7128337号(P7128337)
【発明の名称】「モニタリング装置、モニタリング方法、モニタリングプログラム、および契約管理システム」
【特許権者】損害保険ジャパン株式会社、株式会社エコノミクスデザイン、株式会社ＷＡＮＤ
【発明者】金崎 寛、坂井 豊貴、岡本 実哲、大竹 康弘、丹下 靖英
３【特許番号】特許第7426681号(P7426681)
【発明の名称】商品／サービスの選択時にユーザー視点で横断共通な評価を実現する方法
【特許権者】株式会社マイベスト、株式会社エコノミクスデザイン、合同会社坂井豊貴事務所
【発明者】吉川 徹、竹尾 哲平、坂井 豊貴、河田 陽向
４【特許番号】特許第7454313号(P7454313)
【発明の名称】スコアリング装置、スコアリング方法、およびスコアリングプログラム
【特許権者】株式会社エコノミクスデザイン
【発明者】坂井 豊貴、今井 誠
Books (in Japanese)
共著『メカニズムデザイン』（ミネルヴァ書房 2008年）
単著『マーケットデザイン入門』（ミネルヴァ書房 2010年）
単著『マーケットデザイン』（ちくま新書 2013年）
単著『社会的選択理論への招待』（日本評論社 2013年）
単著『準線形環境におけるメカニズムデザイン』三菱経済研究所（2014年）
編著『メカニズムデザインと意思決定のフロンティア』（慶應義塾大学出版会 2014年）
単著『多数決を疑う』（岩波新書 2015年）
単著『決め方の経済学』（ダイヤモンド社 2016年）
単著『ミクロ経済学入門の入門』（岩波新書2017年）
共著『大人のための社会科』（2017年 有斐閣）
共編著『ニッポン戦後経済史』（NHK出版 2018年）
単著『暗号通貨vs国家』（SB新書 2019年）
共著『メカニズムデザインで勝つ』（日本経済新聞出版社 2020年）
共編著『そのビジネス課題、最新の経済学で「すでに解決」しています。』（日経BP 2022年）
アジアで翻訳された著書たち
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