Dec 27 - Very Hard
Puzzle Copyright © Kevin Stone
Share link – www.brainbashers.com
Reasoning
R1C9 can only be <6>
R1C2 is the only square in column 2 that can be <9>
Squares R7C2 and R7C8 in row 7 form a simple naked pair. These 2 squares both contain the 2 possibilities <67>. Since each of the squares must contain one of the possibilities, they can be eliminated from the other squares in the row.
R7C6 - removing <6> from <136> leaving <13>
Squares R3C2 and R7C2 in column 2 form a simple naked pair. These 2 squares both contain the 2 possibilities <67>. Since each of the squares must contain one of the possibilities, they can be eliminated from the other squares in the column.
R4C2 - removing <6> from <268> leaving <28>
R5C2 - removing <6> from <2456> leaving <245>
R9C2 - removing <6> from <256> leaving <25>
Intersection of column 2 with block 4. The values <48> only appears in one or more of squares R4C2, R5C2 and R6C2 of column 2. These squares are the ones that intersect with block 4. Thus, the other (non-intersecting) squares of block 4 cannot contain these values.
R5C1 - removing <4> from <1456> leaving <156>
R6C3 - removing <4> from <24> leaving <2>
R4C2 can only be <8>
R6C5 is the only square in row 6 that can be <8>
R9C2 is the only square in column 2 that can be <2>
R4C5 is the only square in column 5 that can be <7>
R4C3 is the only square in row 4 that can be <1>
R5C1 is the only square in block 4 that can be <6>
R9C1 can only be <5>
Squares R4C7 and R4C8 in block 6 form a simple naked pair. These 2 squares both contain the 2 possibilities <26>. Since each of the squares must contain one of the possibilities, they can be eliminated from the other squares in the block.
R5C8 - removing <2> from <249> leaving <49>
Intersection of row 9 with block 9. The value <8> only appears in one or more of squares R9C7, R9C8 and R9C9 of row 9. These squares are the ones that intersect with block 9. Thus, the other (non-intersecting) squares of block 9 cannot contain this value.
R8C9 - removing <8> from <5789> leaving <579>
Squares R3C2 and R3C8 in row 3 and R7C2 and R7C8 in row 7 form a Simple X-Wing pattern on possibility <7>. All other instances of this possibility in columns 2 and 8 can be removed.
R6C8 - removing <7> from <47> leaving <4>
R6C2 can only be <5>
R5C8 can only be <9>
R5C9 can only be <5>
R5C2 can only be <4>
R6C7 can only be <7>
R2C7 can only be <2>
R4C7 can only be <6>
R1C8 can only be <1>
R4C8 can only be <2>
R8C7 can only be <5>
R1C1 can only be <4>
R1C5 can only be <2>
R8C1 can only be <7>
R2C3 can only be <6>
R5C5 can only be <1>
R8C3 can only be <4>
R3C2 can only be <7>
R3C8 can only be <8>
R7C2 can only be <6>
R2C1 can only be <1>
R3C4 can only be <1>
R9C8 can only be <6>
R2C9 can only be <7>
R7C8 can only be <7>
R8C9 can only be <9>
R8C5 can only be <6>
R9C9 can only be <8>
R9C5 can only be <9>
R2C6 can only be <8>
R2C4 can only be <9>
R3C6 can only be <6>
R7C4 can only be <3>
R8C6 can only be <2>
R7C6 can only be <1>
R5C4 can only be <2>
R8C4 can only be <8>
R5C6 can only be <3>
R2C5 can only be <4>
Today's Sudoku Puzzles
All daily items change at midnight GMT – set your local time zone.
Note: BrainBashers has a Dark Mode setting.