Planet Sudoku

How do you Sudoku? Introduction to How To's

Solving Techniques

Millions of Free Sudoku Puzzles 4x4, 6x6, 8x8, 9x9, 12x12, to 25x25 at Planet Sudoku!

Planet Sudoku's helpers section will improve your puzzle solving skills.

Show Hints / Candidates will help you see the available pencil values within the cell, row, column, and boxes.

Sudoku How To Technique: Hidden Quint

Extending the rule of Hidden Quad it uses the concept of “If there are five unique hints in five cells within one container, then we know that no other hints could be valid within that container using process of elimination”. Remember all five cells don’t need to have all of the valid five HINTS, they just need to make a unique combination of the five HINTS. The diagram shows ROW R8 CELLS R8C1, R8C4, R8C7, R8C8, and R8C9 having the valid values of {1,2,5,7,9}. With that knowledge we know that no other HINTS within those CELLS are valid, and can be safely removed.

If looking for solutions for cells manually, I would not recommend trying to look for this type of hint reduction method. Other solution patterns will most likely show a positive before this one.

This solving method has been categorized as Hard Sudoku. Try this and other Hard Sudoku solving methods.
Try this Hidden Quint Sudoku puzzle.

Puzzle Number: 188899
Method: HIDDEN QUINT {1,2,5,7,9} - In Block Type: ROW
Found Cell and Hints: s1r8c1 1,7,9; s1r8c4 7; s1r8c7 1,2,5,9; s1r8c8 1,2,5,7,9; s1r8c9 1,2,7,9;
Removing Hints: s1r8c4 4; s1r8c7 4; s1r8c8 4; s1r8c9 4;

Start playing Sudoku online today! We have many different boards and difficulty levels to choose from.