Sep 20 - Very Hard
Puzzle Copyright © Kevin Stone
Share link – www.brainbashers.com
Reasoning
R3C9 can only be <4>
R3C1 can only be <1>
R3C4 can only be <7>
R3C6 can only be <5>
R1C3 is the only square in row 1 that can be <5>
R1C2 is the only square in row 1 that can be <6>
R6C2 can only be <8>
R2C2 can only be <4>
R2C3 can only be <9>
R5C2 can only be <1>
R8C2 can only be <7>
R2C1 can only be <8>
R2C8 is the only square in row 2 that can be <7>
R2C5 is the only square in row 2 that can be <1>
R1C7 is the only square in row 1 that can be <1>
R4C9 is the only square in row 4 that can be <8>
R5C1 is the only square in row 5 that can be <2>
R6C5 is the only square in row 6 that can be <9>
R1C6 is the only square in row 1 that can be <9>
R5C9 is the only square in row 5 that can be <9>
R5C8 is the only square in row 5 that can be <5>
R7C6 is the only square in row 7 that can be <7>
R5C5 is the only square in row 5 that can be <7>
R8C9 is the only square in row 8 that can be <5>
R9C1 is the only square in row 9 that can be <9>
R7C9 is the only square in column 9 that can be <6>
Intersection of column 1 with block 7. The value <4> only appears in one or more of squares R7C1, R8C1 and R9C1 of column 1. These squares are the ones that intersect with block 7. Thus, the other (non-intersecting) squares of block 7 cannot contain this value.
R9C3 - removing <4> from <346> leaving <36>
Squares R1C4<234>, R2C4<23> and R7C4<34> in column 4 form a comprehensive naked triplet. These 3 squares can only contain the 3 possibilities <234>. Since each of the squares must contain one of the possibilities, they can be eliminated from the other squares in the column.
R5C4 - removing <3> from <368> leaving <68>
R9C4 - removing <234> from <23468> leaving <68>
Intersection of column 4 with block 2. The value <2> only appears in one or more of squares R1C4, R2C4 and R3C4 of column 4. These squares are the ones that intersect with block 2. Thus, the other (non-intersecting) squares of block 2 cannot contain this value.
R1C5 - removing <2> from <234> leaving <34>
Squares R2C4, R2C9, R1C4 and R1C9 form a Type-1 Unique Rectangle on <23>.
R1C4 - removing <23> from <234> leaving <4>
R1C5 can only be <3>
R7C4 can only be <3>
R1C9 can only be <2>
R4C5 can only be <6>
R2C4 can only be <2>
R2C9 can only be <3>
R5C4 can only be <8>
R5C6 can only be <3>
R9C4 can only be <6>
R8C6 can only be <1>
R7C1 can only be <4>
R9C6 can only be <8>
R9C3 can only be <3>
R4C3 can only be <4>
R8C1 can only be <6>
R4C8 can only be <3>
R5C3 can only be <6>
R8C8 can only be <4>
R6C7 can only be <6>
R5C7 can only be <4>
R6C1 can only be <3>
R9C7 can only be <2>
R8C5 can only be <2>
R9C8 can only be <1>
R9C5 can only be <4>
R8C7 can only be <3>
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