Master Number: Rules and How to Play
Master Number is a number-guessing deduction game for 2–5 players that takes about 10 minutes. Everyone races to crack the same secret number with hits and blows. Free in your browser, no sign-up.
Setup
- For 2 to 5 players. Playing alone, you face the computer.
- The game picks a secret number (the Master Number) of different digits from 0 to 9. It has three to five digits; the default is four. It may start with 0.
- With Open Numbers on, each player is shown one correct digit in its place. With more players than digits, some players know the same digit. You cannot see which digit anyone else knows.
How to play
- Players guess one at a time in seat order. Enter the right number of different digits and press OK.
- Each guess shows how many digits are right and in the right place (hits) and how many are right but in the wrong place (blows). Every guess and result is visible to everyone.
- Each guess has a 60-second limit. When time runs out the turn passes with no guess (you can switch the limit off).
- Your Open Number is always a hit when you include it. Holding it back gives the other players fewer clues.
Winning and scoring
- The first player to guess every digit of the Master Number wins.
- If nobody cracks it within 100 guesses, the game is a draw.
Defaults on this site
| Item | Default on this site |
|---|---|
| Players | 2–5 players (set automatically by the party size) |
| Turn time limit | None by default (the host can set 30 or 60 seconds) |
| If someone drops mid-game | Reopening on the same device returns you to your seat. If you do not return, the CPU plays in your place. |
| Draws | In ranked play, a draw counts as halfway between a win and a loss for your rating. |
| Source of the rules | Based on the standard reference rules |
Rules supervised by Qdan, Inc. (based on the standard reference rules)
House rules
Defaults follow the standard reference rules. The party can change these.
| Name | Description | Default | Changeable |
|---|---|---|---|
| Digits | Choose three to five digits. Three is best for your first game. | 4 digits | Can be changed |
| Open Numbers | At the start, show each player one correct digit. | On | Can be changed |
| Time limit | Time allowed for each guess. When it runs out, the turn passes with no guess. | 60 seconds | Can be changed |
Terms
- Master Number
- The secret number everyone tries to crack: a row of different digits from 0 to 9.
- Open Number
- One correct digit that only you know from the start.
- Hit (H)
- A digit that is right and in the right place.
- Blow (B)
- A digit that is in the answer but in a different place.
FAQ
Can a digit appear twice?
No. Both the answer and every guess use different digits.
Can the number start with 0?
Yes. 0 is used like any other digit.
What happens when time runs out?
That turn passes with no guess and play moves on. You do not lose.
Play now with these rules
Last updated 2026-09-18 · Run by Qdan, Inc.