Sep 01 - Very Hard
Puzzle Copyright © Kevin Stone
Share link – www.brainbashers.com
Reasoning
R1C4 can only be <7>
R3C4 can only be <4>
R2C4 can only be <9>
R1C5 is the only square in row 1 that can be <2>
R4C6 is the only square in row 4 that can be <2>
R6C2 is the only square in row 6 that can be <4>
R8C1 is the only square in row 8 that can be <4>
R2C3 is the only square in row 2 that can be <4>
R2C2 is the only square in row 2 that can be <5>
R4C2 can only be <9>
R5C2 can only be <6>
R9C8 is the only square in row 9 that can be <2>
R9C5 is the only square in row 9 that can be <4>
R1C2 is the only square in column 2 that can be <1>
R7C3 is the only square in column 3 that can be <9>
R2C1 is the only square in block 1 that can be <7>
R7C1 can only be <6>
R1C1 can only be <8>
Squares R5C7 and R9C7 in column 7 form a simple naked pair. These 2 squares both contain the 2 possibilities <78>. Since each of the squares must contain one of the possibilities, they can be eliminated from the other squares in the column.
R3C7 - removing <7> from <1367> leaving <136>
R6C7 - removing <8> from <138> leaving <13>
R7C7 - removing <7> from <157> leaving <15>
R8C7 - removing <7> from <1567> leaving <156>
R3C9 is the only square in row 3 that can be <7>
Intersection of row 7 with block 8. The value <7> only appears in one or more of squares R7C4, R7C5 and R7C6 of row 7. These squares are the ones that intersect with block 8. Thus, the other (non-intersecting) squares of block 8 cannot contain this value.
R8C6 - removing <7> from <1379> leaving <139>
R9C6 - removing <7> from <379> leaving <39>
R7C6 is the only square in column 6 that can be <7>
Intersection of column 5 with block 5. The values <79> only appears in one or more of squares R4C5, R5C5 and R6C5 of column 5. These squares are the ones that intersect with block 5. Thus, the other (non-intersecting) squares of block 5 cannot contain these values.
R6C6 - removing <9> from <369> leaving <36>
Intersection of column 9 with block 9. The value <9> only appears in one or more of squares R7C9, R8C9 and R9C9 of column 9. These squares are the ones that intersect with block 9. Thus, the other (non-intersecting) squares of block 9 cannot contain this value.
R8C8 - removing <9> from <1679> leaving <167>
Squares R3C5 and R3C7 in row 3 and R7C5 and R7C7 in row 7 form a Simple X-Wing pattern on possibility <1>. All other instances of this possibility in columns 5 and 7 can be removed.
R6C7 - removing <1> from <13> leaving <3>
R8C7 - removing <1> from <156> leaving <56>
R6C4 can only be <8>
R6C6 can only be <6>
R6C5 can only be <9>
R2C6 can only be <1>
R2C9 can only be <8>
R3C5 can only be <6>
R2C8 can only be <6>
R9C9 can only be <9>
R3C3 can only be <3>
R3C7 can only be <1>
R7C7 can only be <5>
R6C8 can only be <1>
R7C5 can only be <1>
R8C7 can only be <6>
R8C8 can only be <7>
R8C2 can only be <3>
R4C8 can only be <8>
R9C7 can only be <8>
R5C7 can only be <7>
R9C6 can only be <3>
R8C9 can only be <1>
R1C8 can only be <3>
R1C3 can only be <6>
R4C3 can only be <5>
R5C8 can only be <9>
R5C5 can only be <5>
R8C4 can only be <5>
R8C6 can only be <9>
R9C2 can only be <7>
R4C4 can only be <3>
R4C5 can only be <7>
R5C3 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 setting.