A diary app that helps you notice how your "good days" change
Just pick one of three choices each day.
Choosing between "Good / Okay / Bad" takes three seconds — and over time, it reveals how your own definition of a "good day" is quietly changing.
■ Nothing to write. That's why it lasts.
Three Choice Diary is a diary for people who could never keep one. There's nothing to think up, so even on busy days or low days, you're done in three seconds. Miss a day? No guilt at all.
■ Made for you if…
・Your diaries always fizzle out after a few days
・You want to understand your own feelings and values better
・Your days feel like they're just passing by
・You want a calm, ad-free app
■ Four steps that change you
STEP 1 | Keep recording
Three seconds, three choices. Simple enough that you won't give up — first, we help you keep going.
STEP 2 | Know yourself
Grounded in psychology (Schwartz's theory of values, the VIA character strengths, and the Big Five), AI analyzes your records to reveal your values, strengths, and personality — including sides of yourself you never noticed.
STEP 3 | Find insight
A gentle daily report puts the day's emotions and context into words. Weekly and monthly reports — plus special reports — mean your diary never ends at "just written down."
STEP 4 | Notice your changing yardstick
As your records add up, you'll see how your standard for a "good day" has shifted over time. You'll notice the gap between assumptions and true feelings, and learn to cherish what a "good day" means to you now.
■ Psychology, woven into every day
Supervised by a Doctor of Psychology, built on the mission of turning academic insight into tools you can use every day.
"The 'calendar circle-and-cross method' I wrote about in my book The Mechanism of Happiness has evolved into this."
— Prof. Takashi Maeno (Dean, Faculty of Well-being Studies, Musashino University)
"Turning psychological insight into a tool for everyday life is an ambitious undertaking."
— Prof. Shigehiro Oishi (Professor of Psychology, University of Chicago)
■ Use it with peace of mind
・No ads, ever
・Calm, gentle design
・AI comments that stay faithful and precise to your diary
Try it free for one week.
Your change begins the moment you choose today's "good day."
