Feb 04 - Very Hard
Puzzle Copyright © Kevin Stone
Share link:
Reasoning
R7C5 can only be <1>
R2C2 is the only square in row 2 that can be <7>
R5C4 is the only square in row 5 that can be <7>
R5C3 is the only square in row 5 that can be <4>
R6C2 can only be <1>
R6C6 can only be <5>
R4C2 can only be <6>
R6C4 can only be <4>
R4C6 is the only square in row 4 that can be <1>
R5C6 is the only square in row 5 that can be <6>
R7C8 is the only square in row 7 that can be <7>
R8C1 is the only square in column 1 that can be <1>
R2C4 is the only square in column 4 that can be <5>
R8C8 is the only square in column 8 that can be <4>
Squares R8C4 and R8C6 in row 8 form a simple naked pair. These 2 squares both contain the 2 possibilities <39>. Since each of the squares must contain one of the possibilities, they can be eliminated from the other squares in the row.
R8C2 - removing <3> from <235> leaving <25>
R8C3 - removing <3> from <3568> leaving <568>
Intersection of column 1 with block 1. The value <6> only appears in one or more of squares R1C1, R2C1 and R3C1 of column 1. These squares are the ones that intersect with block 1. Thus, the other (non-intersecting) squares of block 1 cannot contain this value.
R2C3 - removing <6> from <368> leaving <38>
Intersection of block 6 with column 8. The value <8> only appears in one or more of squares R4C8, R5C8 and R6C8 of block 6. These squares are the ones that intersect with column 8. Thus, the other (non-intersecting) squares of column 8 cannot contain this value.
R1C8 - removing <8> from <389> leaving <39>
R2C8 - removing <8> from <123689> leaving <12369>
Squares R3C2 and R3C9 in row 3 and R7C2 and R7C9 in row 7 form a Simple X-Wing pattern on possibility <5>. All other instances of this possibility in columns 2 and 9 can be removed.
R1C2 - removing <5> from <359> leaving <39>
R8C2 - removing <5> from <25> leaving <2>
R8C9 - removing <5> from <2568> leaving <268>
R9C2 can only be <3>
R9C3 can only be <6>
R1C2 can only be <9>
R1C8 can only be <3>
R3C5 is the only square in row 3 that can be <3>
R2C6 can only be <9>
R8C6 can only be <3>
R8C4 can only be <9>
R4C4 can only be <3>
R2C3 is the only square in row 2 that can be <3>
R3C8 is the only square in row 3 that can be <9>
R4C8 can only be <8>
R4C5 can only be <9>
R6C8 can only be <2>
R6C5 can only be <8>
R9C8 can only be <1>
R5C7 can only be <9>
R9C7 can only be <2>
R2C8 can only be <6>
R2C1 can only be <8>
R3C9 can only be <5>
R3C2 can only be <4>
R7C9 can only be <8>
R1C7 can only be <8>
R5C5 can only be <2>
R7C1 can only be <4>
R2C9 can only be <2>
R8C9 can only be <6>
R8C7 can only be <5>
R8C3 can only be <8>
R1C3 can only be <5>
R2C7 can only be <1>
R3C1 can only be <6>
R7C2 can only be <5>
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