AI Diary App '3-Choice Diary' Recommended by Leading Happiness Scholar Professor Takashi Maeno (Musashino University) and University of Chicago Professor Shigehiro Oishi

Smartphone App 3-Choice Diary

ALL GOOD (Headquarters: Shinjuku-ku, Tokyo; Representative: Masao Saeki) announces that its AI diary app "3-Choice Diary," developed and operated by the company, has received endorsements from Professor Takashi Maeno of Musashino University, a leading authority in happiness studies, and Professor Shigehiro Oishi of the University of Chicago, world-renowned for his research on subjective well-being and psychological richness. Masao Saeki, the representative, holds a doctorate under Professor Maeno's guidance and has served as a visiting researcher under Professor Oishi.

Background of the Endorsement

The app's endorsement is part of a strategy to further enhance the credibility and brand value of "3-Choice Diary" as a psychology-based diary app. Masao Saeki, representative of ALL GOOD, pursued well-being research, including the four factors of happiness, under the guidance of Professor Takashi Maeno during his doctoral program at Keio University Graduate School of System Design and Management. He also studied abroad as a visiting researcher under Professor Shigehiro Oishi of the University of Chicago (then a professor at the University of Virginia), receiving guidance and publishing three peer-reviewed international papers and one domestic paper. The research for which Representative Masao Saeki received the Behavioral Economics Society Encouragement Award was also a collaborative effort with both professors. Receiving formal endorsements for his app, now as a professional, from his two university mentors symbolizes the app's journey toward bridging academia and practical application.

Endorsement Messages

Professor Takashi Maeno's Endorsement

The "calendar circle-cross method" I wrote about in my book "Mechanisms of Happiness" has evolved. I sincerely hope that this app, developed by my student and happiness researcher Saeki-san, will improve the happiness of many people.

Professor Shigehiro Oishi's Endorsement

Reflecting on daily life through journaling is an effective practice for fostering psychological richness. Applying psychological knowledge to daily tools is a challenging endeavor, but Saeki-kun's app shows great potential. I hope it will enrich many people's lives.

About 3-Choice Diary

Diary Entry Screen

The concept is to increase good days.

It is a diary app where users subjectively evaluate and record their day with a choice of three options: good, average, or bad. In addition to the three choices, users can attach diary text and photos. The UI/UX is designed to reduce the burden of journaling by allowing users to make quick marks when busy or write detailed entries when they have time.

The app offers 10 color themes, 7 three-choice icons, and 6 font styles, all freely selectable. Furthermore, user diaries are encrypted and cannot be read even by the developers, ensuring users can use the app with peace of mind.

Reports are delivered when you continue journaling.

When you write a diary entry, an AI-generated reflection report is delivered. Reports include daily, weekly, monthly, special, and psychological reports, and users can comment on each report. Through report generation and comments, the AI accumulates knowledge about the user, and by continuing to journal, the AI delivers reports that better understand the user.

An action suggestion feature is also available, which proposes next steps based on diary entries. We hope that gradually continuing to use this feature will increase users' good days.

It also links with Apple Health, incorporating daily steps and sleep duration into the reflection reports.

Example of Cognitive Distortion Report

Psychological Report Screen

Estimating psychological constructs from diary entries.

Psychological constructs such as Schwartz's values, attachment styles, and cognitive distortions are estimated from diary entries and delivered to users as psychological reports within the app.

Moving forward, we plan to increase the number of targeted psychological constructs to nearly 40 and ask Professor Takashi Maeno for guidance on AI prompts for psychological reports related to the four factors of happiness, and Professor Shigehiro Oishi for guidance on psychological richness.

Endorser Profiles

Professor Takashi Maeno

Dean of the Faculty of Well-being at Musashino University, Professor Emeritus at Keio University. Specialties: well-being, innovation. Doctor of Engineering. After working at Canon Inc., visiting researcher at the University of California, Berkeley, visiting professor at Harvard University, and professor at Keio University Faculty of Science and Technology, he assumed his current position. Representative Director of the Well-being Society. Vice President of the Japan System Design Society.

His many books include "Can We Create AI with a Mind? Or, Do Humans Even Have Minds?" (2026), "30 Habits for Happy Work" (2023), "New Theory of Happiness in a Dystopian Age" (2022), and "Mechanisms of Happiness - Practical Introduction to Happiness Studies" (2013).

Professor Takashi Maeno

Professor Shigehiro Oishi

Professor Shigehiro Oishi

Marshall Field Professor of Psychology at the University of Chicago. Graduated from International Christian University (B.A.), Columbia University (M.A.), and University of Illinois (Ph.D.). Happiness, life