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Which friend is your lucky charm?
Start with your birthday. Then invite friends to find your fit through Korean fortune-telling.
Grab it. Give it a spin. Turn ↻
Find my lucky charm
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It starts with you.
Your birthday is the starting point for your saju-inspired piece.
For ages 18 and over. Use your own birth details. Eligibility & terms
Calendar calculated on this device. No birth data is sent or saved; refreshing clears it. Readings are for fun.
Birth details are stored on this service, not shown to friends. Delete them in My access & privacy. Saju readings are cultural entertainment, not verified predictions.
A little grounding.
The Root Wood · 목
Your five elements
How this reading is made
Which friend is your lucky charm?
Invite friends to compare your compatibility scores.
See my puzzle
Sign in with Google to create your puzzle.
Google sign-in is unavailable in this preview. Your free reading is still available.
Your people, your story
Your full reading is unlocked.
Save my piece
My piece Save puzzle
Alex ’s puzzle 0 friends
Your full reading is unlocked. Read my full reading
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What’s our score?
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Fit
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Who’s your best match? Score / 100
1 Your first friend ??/ 100
Tap a friend to read about your connection.
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Calculated with the Bestie formula. Sample birthdays are labeled. Scores are for fun, not a measure of friendship.
Invite a friend
See your score and what makes you click.
Compare a friend’s birthday
Try fictional birthdays — scores are calculated + Add a sample friend Preview 90+ animation Try 100 sample people
Pieces click at 90+. The animation preview is separate and never enters your rankings.
There’s room for someone new, too.
Find a fit at my school ↗
My puzzle
A fit you haven’t met.
Find someone you might click with at your school.
Demo supports Berkeley and Stanford. No email is sent.
Back UC Berkeley
A fictional campus sample — / 100
You make things happen.
Say hello · $1 Chat opens when they accept. This is a demo.
Your hello is on its way. They can choose whether to connect.
Demo: they accept
Avery found their place.
Avery’s piece is now part of your puzzle.
A 99? We should probably get coffee.
Demo chat. Messages are not sent to anyone.
See Avery in my puzzle
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How this reading is made
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You just click.
You + Maya 96 / 100
The friend who gets you moving.
Who else do you click with?
Invite more friends to compare your scores.
See my puzzle
Sign in with Google to create your puzzle.
Google sign-in is unavailable in this preview. Your shared score is already saved.
How this score is calculated Base 50 + raw factors, clamped to 10–105, then mapped to 61–99. These are the original Bestie app’s weights, not a probability. With the current factors, the result cannot exceed 97.
New pieces with a birth city use historical time zones and longitude-based mean solar time. Older pieces keep their original calculation. Unknown times use a partial chart. This score is not a verified prediction about a person.
A little saju, a starting point for a conversation.
Read our full story · $1
Rule-based explanation. Demo unlock — no payment collected.
Save our two pieces
Back to my people
Manage connection Remove from my puzzle
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What’s our score?
Send your piece to a friend. When they join, their piece becomes part of your puzzle.
When one friend joins your link, your full personal reading opens too.
Copy invitation
Share invitation
Your invitation link
Compare a birthday on this device
Preview a friend joining
Local prototype: shared links only work on this device.
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Another piece of your world.
Compare two birthdays on this device. Ask your friend before entering their details, or try fictional ones.
Local only. Nothing is sent or saved; refreshing clears these details.
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Send a hello?
They’ll see your alias, your piece and your shared reading. Your birthday stays private.
Connection request $1
Messaging After they accept Send demo request
No real charge or external request.
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Your pieces, to keep.
Download image
Save it, send it, put it in the group chat.
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My page
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What is saju?
Saju is a Korean fortune-telling tradition that interprets your birth year, month, day and time.
Gwiin uses it to explore your traits and how you connect with friends. Start with your own piece, then invite friends to see how you fit together.
Readings and scores are cultural interpretations, not scientific measures or predictions about your relationships.
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Account settings
Sign in to keep your puzzle across devices.
Continue with Google
Google sign-in is unavailable in this local preview.
Birth details
City data: GeoNames · CC BY 4.0
Removed connections
Privacy & data
Friends see your alias, piece, shared score and reading—not your birth details or other friends. Anyone with your invitation link can see your alias and piece type. Privacy & deletion details
Replace invitation link
Delete my puzzle and birth details
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Delete your puzzle?
This deletes your profile, birth details, Google link, connections and saved readings from the active Gwiin database. Your piece and your pair’s saved readings disappear from your friends’ accounts too. This cannot be undone.
It does not delete your Google account, exported images or copies someone saved. Provider logs, backups and any payment-provider records are separate. Read the limits
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Our full story. What you bring to each other. Where you may miss each other. One thing to try together.
One saved reading · $1 USD · no subscription.
Generate an AI interpretation using our calculated saju charts. Raw birthdays, names and payment details are not sent to the AI provider. This is for reflection and fun.
Continue to checkout · $1
The purchase belongs to your Google-linked Gwiin account. Sign in with the same Google account to return on another device. If generation fails, retry without paying again.