# Naked Quad

A Naked Quad occurs when exactly four digits are candidates in four cells of a house. You can eliminate these digits from the other cells in this house.In the sudoku diagram below, in the third row, only the four digits 3, 4, 6 and 8 can be placed in the R3C1, R3C2, R3C3 and R3C9 cells. Therefore, you can eliminate these digits from the other cells of this row. Thanks to this, the digit 6 can only be placed in the R1C4 cell in the upper middle box.