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Grandmaster Grid
Grandmaster Grid is a hard sudoku contest: one grid, 25 minutes, one play per device, and a clock kept on the server so every finishing time is fair. Players open one link on their phone, with no account.
- Made for
- Teams and training
- Difficulty
- Hard
- Duration
- 25 min
- Steps
- 1
- Locks used
- Sudoku
Try it before you copy it
What this template contains
step 1 · Sudoku
The grandmaster's grid
⏱️ One hard sudoku, twenty-five minutes.
🧩 Every row, every column and every 3x3 box holds 1 to 9 exactly once.
🧠 No guessing needed: pure logic gets you there.
Ideas to make it yours
- Run it as a lunchtime office contest and post the fastest times
- Use it as the final round of a puzzle night
- Swap in an easier grid for a class or a family evening
How to use this template
- 1
Play it here first, exactly as your players will.
- 2
Copy it into the builder, then change the codes, the clues and the locked content.
- 3
Publish and share the link or the QR code. Players need no app and no account.
Questions about this template
- How hard is the grid?
- It is rated hard. It can be solved by logic alone, without guessing, but it calls for more than the simple one-candidate moves. Beginners will find 25 minutes tight.
- How do you keep a sudoku contest fair?
- Each device plays once and the clock runs on the server, not on the phone, so changing the phone's time does not help. Everyone gets the same grid and the same 25 minutes.
- Are there hints?
- Only the rules, as in a real contest. A wrong cell shows in red, so a player knows something clashes without being told the answer.
- Is this template free?
- Playing it and editing it in the builder are free for everyone, and players never pay. See current plans and features on the pricing page.
- Can I change the answers and the texts?
- Yes. Every code, clue, hint and piece of locked content opens in the builder, and nothing is saved until you publish.
- What do players need?
- A phone or a computer with a browser. They open your link or scan your QR code, and never create an account.
- How long does it take to play?
- About 25 minutes, from the first lock to the locked content.
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