Crack the 4-digit code
A duel of logic: crack your opponent's code before they crack yours. You never see their code — only a score that tells you how close you are.
Free to play · 5 ranked matches a day · No ads
The 4 is in the right place. The 1 and 2 are in the code but somewhere else. The 8 isn't in it at all.
How to play
Every guess is a clue
Every code has 4 different digits and never starts with 0. After each guess you get a score — nothing else.
Read the score
- +1 right digit, right spot
- −2 right digit, wrong spot
- anything else isn't in the code
- First to +4−0 wins the duel
Let the keypad help
As you guess, the keypad marks digits it has worked out from your scores — so you can focus on placing them instead of re-deriving them.
- Green dot this digit is in the code
- Red dot this digit is not in the code
Play your way
Three ways to duel
Ranked 1v1
Real opponents, live ELO. Your rating decides who you face — climb higher to meet tougher players.
Play with friends
Create a private room, share the link or the 6-character code, and duel anyone you want.
Solo practice
Level-based puzzles and a smart bot that prunes possibilities the same way a good player does.
The rules
Simple to learn, hard to master
What makes a valid code
- Exactly 4 digits
- All four digits are different
- It never starts with 0
- So the range is 1023 – 9876 — 4,536 possible codes
How a match runs
- Both players pick a secret code
- You take turns guessing, one guess each
- Every guess comes back scored +X−Y
- First to score +4−0 takes the win and the rating
Ready to duel?
Crack your opponent's secret code before they crack yours.