Dec 09 - Very Hard
Puzzle Copyright © Kevin Stone
Share link – www.brainbashers.com
Reasoning
R3C6 can only be <3>
R3C4 can only be <4>
R4C6 can only be <5>
R6C6 can only be <8>
R1C5 can only be <1>
R2C5 can only be <5>
R4C4 can only be <3>
R7C6 can only be <6>
R9C5 can only be <3>
R6C4 can only be <2>
R7C4 can only be <5>
R5C5 can only be <7>
R8C5 can only be <8>
R2C1 is the only square in row 2 that can be <9>
R5C1 is the only square in row 5 that can be <5>
R5C9 is the only square in row 5 that can be <8>
R7C3 is the only square in row 7 that can be <2>
R8C8 is the only square in row 8 that can be <4>
R9C3 is the only square in row 9 that can be <4>
R9C7 is the only square in row 9 that can be <5>
R8C2 is the only square in column 2 that can be <1>
Squares R2C9 and R8C9 in column 9 form a simple naked pair. These 2 squares both contain the 2 possibilities <36>. Since each of the squares must contain one of the possibilities, they can be eliminated from the other squares in the column.
R3C9 - removing <6> from <167> leaving <17>
R7C9 - removing <3> from <137> leaving <17>
Intersection of block 4 with column 3. The value <7> only appears in one or more of squares R4C3, R5C3 and R6C3 of block 4. These squares are the ones that intersect with column 3. Thus, the other (non-intersecting) squares of column 3 cannot contain this value.
R1C3 - removing <7> from <378> leaving <38>
R3C3 - removing <7> from <678> leaving <68>
Intersection of block 6 with column 7. The value <7> only appears in one or more of squares R4C7, R5C7 and R6C7 of block 6. These squares are the ones that intersect with column 7. Thus, the other (non-intersecting) squares of column 7 cannot contain this value.
R1C7 - removing <7> from <378> leaving <38>
R3C7 - removing <7> from <1678> leaving <168>
R7C7 - removing <7> from <137> leaving <13>
Squares R1C3 and R1C7 in row 1 form a simple naked pair. These 2 squares both contain the 2 possibilities <38>. Since each of the squares must contain one of the possibilities, they can be eliminated from the other squares in the row.
R1C2 - removing <3> from <237> leaving <27>
R1C8 - removing <3> from <237> leaving <27>
Squares R1C3 and R1C7 in row 1 and R6C3 and R6C7 in row 6 form a Simple X-Wing pattern on possibility <3>. All other instances of this possibility in columns 3 and 7 can be removed.
R7C7 - removing <3> from <13> leaving <1>
R7C9 can only be <7>
R7C1 can only be <3>
R3C9 can only be <1>
R9C8 can only be <6>
R9C2 can only be <7>
R5C8 can only be <3>
R8C9 can only be <3>
R5C2 can only be <6>
R2C8 can only be <2>
R6C7 can only be <7>
R6C3 can only be <3>
R4C7 can only be <6>
R8C1 can only be <6>
R3C1 can only be <7>
R2C9 can only be <6>
R1C2 can only be <2>
R1C8 can only be <7>
R2C2 can only be <3>
R3C7 can only be <8>
R3C3 can only be <6>
R1C7 can only be <3>
R4C3 can only be <7>
R1C3 can only be <8>
Today's Sudoku Puzzles
All daily items change at midnight GMT – set your local time zone.
Note: BrainBashers has a Dark Mode option – I recommend not using your browser's dark mode or extensions for BrainBashers