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Sudoku How To Technique: Naked Quad

Extending the rule of Naked Pair and Naked Triple one step further it uses the concept of “it has to be one of these four, therefore it can’t be anywhere else within that block”, with the same rule of the four unique CELLS need to have a combination of four unique HINTS within the shared BLOCK. In the diagram we have a unique set of four hints within BOX 3 on CELLS R4C6 {3,8}, R5C4 {3,4,9}, R5C6 {3,4,9}, and R6C6 {8,9}.

This allows us to know that CELL R4C4 can no longer have HINT values of {3}. This same concept applies to the Naked Quint hit reduction method.

This solving method has been categorized as Medium Sudoku. Try this and other Medium Sudoku solving methods.
Try this Naked Quad Sudoku puzzle.

Puzzle Number: 1053222
Method: NAKED QUAD {} - In Block Type: BOX
Found Cell and Hints: s1r4c6 3,8; s1r5c4 3,4,9; s1r5c6 3,4,9; s1r6c6 8,9;
Removing Hints: s1r4c4 3;

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