Nine
Fill the empty cells of a 9×9 chip so every row, column and 3×3 box has 1 to 9 once.
How to play
Tap a cell, then tap a number. Or move with the arrow keys and press 1–9. P pauses. A dimmed number means all nine are placed, or it was already wrong in that cell.
Rules and score
The chip heats up over time. You start with 60 seconds of room, and each wrong number takes 5 seconds off. Fill the chip to cool it down and get time back: 30 s at first, less for later chips, down to 20 s (up to 90 s). Run out and it overheats — game over. A filled chip scores 1 per empty cell. The first chip has 8 empty cells, then 12, 16, 20, 24, then two more each time up to 36. Every chip has one answer and can be solved by logic alone.
Tips
- Start with the fullest row, column or box.
- Pick one number and scan the whole chip for where it can go.
- Look for a cell where only one number fits.
- Each guess that's wrong costs 5 seconds. Sure moves are faster.
FAQ
- What happens to a wrong number?
- It isn't placed; you lose 5 seconds and that number dims for that cell.
- Is there a time limit?
- Besides the heat, a game is at most 10 minutes.