Platon Sudoku · Sudoku Study

Be Sure Before You Fill · Sudoku

Look at the highlighted row, column and box. Both 3 and 7 are still possible here; we cannot decide yet.

This course is adapted from Platon Sudoku App. Read the complete example here, then continue learning and practising in the app.

What can go here?

Look at the highlighted row, column and box. Both 3 and 7 are still possible here; we cannot decide yet.

Our puzzles have one complete solution, but a candidate is not an answer. Note 3 and 7, then look elsewhere.

In this new cell, the digits already in its row, column and box rule out every possibility except 7.

Once 7 is filled, the original cell can no longer contain 7. Only 3 remains.

Solve a cell you can justify, then return to the uncertain ones. Each confirmed digit can reveal a new clue.

This course is adapted from Platon Sudoku App. Read the complete example here, then continue learning and practising in the app.