CLUEKITE

Nonocross Level 21 Answer

8x8 grid, reveals: Smile

Level 21 is a 8x8 grid with 52 filled cells out of 64. The easiest first move is Row 3: its clue 8 fills the whole line. Most players finish it in about 5 minutes. Below is the full solved grid, followed by every logical step if you would rather solve it yourself.

Level 21 solved grid

4688886446888864

Filled cells are shaded. The numbers are the row and column clues from the game.

Checked by the Cluekite solver against all 8 row and 8 column clues on 27 October 2026.

Open the grid as an image

Step-by-step hints for Level 21

Press the button to reveal one step at a time. Each step fills or crosses out cells in a single row or column, in the order a careful player would find them.

  1. Step 1: Row 3 - the clue 8 fills the whole line. (8 filled)
  2. Step 2: Row 4 - the clue 8 fills the whole line. (8 filled)
  3. Step 3: Row 5 - the clue 8 fills the whole line. (8 filled)
  4. Step 4: Row 6 - the clue 8 fills the whole line. (8 filled)
  5. Step 5: Row 2 - the clue 6 leaves only 2 free cells, so the middle of each long block must be filled. (4 filled)
  6. Step 6: Row 7 - the clue 6 leaves only 2 free cells, so the middle of each long block must be filled. (4 filled)
  7. Step 7: Column 1 - every block of 4 is already placed, so the remaining cells are empty. (4 crossed out)
  8. Step 8: Column 8 - every block of 4 is already placed, so the remaining cells are empty. (4 crossed out)
  9. Step 9: Row 1 - with the cells already marked, only one arrangement of 4 fits these positions. (2 filled)
  10. Step 10: Row 2 - with the cells already marked, only one arrangement of 6 fits these positions. (2 filled)
  11. Step 11: Row 7 - with the cells already marked, only one arrangement of 6 fits these positions. (2 filled)
  12. Step 12: Column 2 - every block of 6 is already placed, so the remaining cells are empty. (2 crossed out)
  13. Step 13: Column 7 - every block of 6 is already placed, so the remaining cells are empty. (2 crossed out)
  14. Step 14: Row 1 - with the cells already marked, only one arrangement of 4 fits these positions. (2 filled)
  15. Step 15: Row 8 - with the cells already marked, only one arrangement of 4 fits these positions. (4 filled)

Level 21 at a glance

Grid size
8x8
Filled cells
52 of 64 (81 percent)
Longest clue
8 in Row 3
Logical steps
15
Picture
Smile
Difficulty
Medium
Other valid fillings
no, the clues allow exactly one filling

The hidden picture

Tips for 8x8 grids

On a 8x8 grid, start with every row and column whose clues cover more than half its length. The overlap fixes the middle cells, and each filled cell gives you a head start in the crossing line.

Where players go wrong on Level 21

  • The longest line is Row 3 with the clue 8, and it is a full line: its blocks and gaps add up to the whole length, so fill it first and let it anchor the lines that cross it.
  • Row 1 has the fewest filled cells (4). Cross out its empty cells early; they keep the columns honest.
  • The last line the logic finishes is Row 8. If you are stuck there, every other line is already done, so recount its clue 4.

More Nonocross levels

Level 197x7MediumLevel 207x7MediumLevel 228x8MediumLevel 238x8Medium

All Nonocross answers | How to Play Nonocross

Does your Level 21 look different? Email us with a screenshot and we will check it.