Platon Sudoku · Sudoku Study
Full House · Step-by-step example
A row, column, or box has exactly one empty cell. Fill the empty cell with the one missing digit.
This course is adapted from Platon Sudoku App. Read the complete example here, then continue learning and practising in the app.
View on Google PlayRecognize the pattern
A row, column, or box has exactly one empty cell.
How to find it
Look for a nearly complete row, column, or box, then compare its filled digits with 1 through 9.
What it allows
Fill the empty cell with the one missing digit.
Avoid the mix-up
Count empty cells in the chosen region. A naked single may be the only candidate for a cell even when several cells are still empty.
Step-by-step example · Row
This example starts from a saved intermediate position. Its candidates include earlier logical eliminations; they are not fresh automatic notes.
Blue: evidence. Green: conclusion. Crossed-out digits: eliminated candidates. R1C1 means row 1, column 1.
Step 1 · Where to look
row 5 has only R5C3 left empty. The missing digit is 4, so R5C3 must be 4.
Step 2 · Conclusion
R5C3=4 is forced by this pattern.
What it allows
R5C3=4 is forced by this pattern.
Step-by-step example · Column
This example starts from a saved intermediate position. Its candidates include earlier logical eliminations; they are not fresh automatic notes.
Blue: evidence. Green: conclusion. Crossed-out digits: eliminated candidates. R1C1 means row 1, column 1.
Step 1 · Where to look
column 9 has only R4C9 left empty. The missing digit is 4, so R4C9 must be 4.
Step 2 · Conclusion
R4C9=4 is forced by this pattern.
What it allows
R4C9=4 is forced by this pattern.
Step-by-step example · Box
This example starts from a saved intermediate position. Its candidates include earlier logical eliminations; they are not fresh automatic notes.
Blue: evidence. Green: conclusion. Crossed-out digits: eliminated candidates. R1C1 means row 1, column 1.
Step 1 · Where to look
box 9 has only R7C7 left empty. The missing digit is 5, so R7C7 must be 5.
Step 2 · Conclusion
R7C7=5 is forced by this pattern.
What it allows
R7C7=5 is forced by this pattern.
Practice
This course is adapted from Platon Sudoku App. Read the complete example here, then continue learning and practising in the app.
View on Google Play