Ready to put the Naked Quad into action? This page is designed for you to practice and master Naked Quad with positions from real Sudoku puzzles.
Every board above is a position from a real puzzle where the Naked Quad is the next step. Tap the candidates it removes (or select a cell and press the digit) and press Check. If you’re stuck, Show me gives the answer and Next puzzle loads another. Want to watch one first? Switch to Worked example.
Quick Reminder: What is a Naked Quad?
A naked quad is four cells in one row, column or box whose candidates, taken together, are only four digits. Those four digits must fill those four cells, so they can be removed from every other cell in the house. Not every cell needs all four digits.
Want a full step-by-step guide? Read the Naked Quad technique article
How to Practice
- In each house, look for four cells with no more than four candidates each.
- Check that the four cells use only four different digits between them, then remove those digits from the rest of the house.
- On the board, tap each of those candidates to remove it.
- Press Check. On your first try you see how many you found; on the second, the ones you missed get a dashed ring.
Start Practicing on Full Puzzles
Once you can find the Naked Quad on most boards without pressing Show me, take it into a full game. Hard puzzles are where this technique starts to come up, and the step-by-step solver will name the technique each time you get stuck.