Oct 12 - Very Hard
Puzzle Copyright © Kevin Stone
Share link – www.brainbashers.com
Reasoning
R1C1 can only be <5>
R2C2 can only be <8>
R3C1 can only be <6>
R9C1 can only be <1>
R7C1 can only be <3>
R5C1 can only be <8>
R1C5 is the only square in row 1 that can be <4>
R1C7 is the only square in row 1 that can be <1>
R2C6 is the only square in row 2 that can be <3>
R6C3 is the only square in row 6 that can be <3>
R5C9 is the only square in row 5 that can be <3>
R6C2 is the only square in row 6 that can be <6>
R6C8 is the only square in row 6 that can be <1>
R4C2 is the only square in row 4 that can be <1>
R8C5 is the only square in row 8 that can be <6>
R9C3 is the only square in row 9 that can be <6>
R3C7 is the only square in column 7 that can be <9>
R3C9 is the only square in row 3 that can be <8>
R4C8 is the only square in column 8 that can be <8>
R6C6 is the only square in row 6 that can be <8>
Squares R3C3 and R3C6 in row 3 form a simple naked pair. These 2 squares both contain the 2 possibilities <27>. Since each of the squares must contain one of the possibilities, they can be eliminated from the other squares in the row.
R3C4 - removing <27> from <1257> leaving <15>
R3C5 - removing <7> from <157> leaving <15>
Intersection of row 9 with block 9. The value <4> 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.
R7C7 - removing <4> from <2458> leaving <258>
R7C9 - removing <4> from <24> leaving <2>
R1C9 can only be <7>
R1C3 can only be <2>
R9C9 can only be <4>
R2C8 can only be <2>
R3C3 can only be <7>
R3C6 can only be <2>
R5C7 is the only square in row 5 that can be <2>
R8C4 is the only square in row 8 that can be <2>
Intersection of row 5 with block 4. The value <4> only appears in one or more of squares R5C1, R5C2 and R5C3 of row 5. These squares are the ones that intersect with block 4. Thus, the other (non-intersecting) squares of block 4 cannot contain this value.
R4C3 - removing <4> from <459> leaving <59>
Squares R5C2 and R8C2 in column 2 and R5C8 and R8C8 in column 8 form a Simple X-Wing pattern on possibility <5>. All other instances of this possibility in rows 5 and 8 can be removed.
R5C3 - removing <5> from <459> leaving <49>
R5C5 - removing <5> from <579> leaving <79>
R3C5 is the only square in column 5 that can be <5>
R3C4 can only be <1>
R7C5 is the only square in row 7 that can be <1>
R7C7 is the only square in row 7 that can be <8>
R9C7 can only be <7>
R9C5 can only be <8>
R8C8 can only be <5>
R8C2 can only be <4>
R5C8 can only be <7>
R5C5 can only be <9>
R8C6 can only be <7>
R5C2 can only be <5>
R7C3 can only be <5>
R4C3 can only be <9>
R5C3 can only be <4>
R2C5 can only be <7>
R4C6 can only be <4>
R2C4 can only be <9>
R4C7 can only be <5>
R7C6 can only be <9>
R6C4 can only be <5>
R4C4 can only be <7>
R6C7 can only be <4>
R7C4 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.