Feb 16 - Super Hard
Puzzle Copyright © Kevin Stone
Share link:
Reasoning
R2C3 can only be <4>
R9C6 can only be <9>
R7C6 is the only square in row 7 that can be <8>
R7C4 is the only square in row 7 that can be <4>
R7C3 is the only square in row 7 that can be <9>
R3C2 is the only square in column 2 that can be <8>
Squares R4C4 and R4C9 in row 4 form a simple naked pair. These 2 squares both contain the 2 possibilities <37>. Since each of the squares must contain one of the possibilities, they can be eliminated from the other squares in the row.
R4C1 - removing <3> from <356> leaving <56>
R4C3 - removing <37> from <135678> leaving <1568>
R4C6 - removing <3> from <135> leaving <15>
R4C7 - removing <37> from <3678> leaving <68>
Squares R1C3 and R8C3 in column 3 form a simple naked pair. These 2 squares both contain the 2 possibilities <23>. Since each of the squares must contain one of the possibilities, they can be eliminated from the other squares in the column.
R3C3 - removing <23> from <235> leaving <5>
R5C3 - removing <3> from <137> leaving <17>
R6C3 - removing <3> from <35678> leaving <5678>
R9C3 - removing <2> from <126> leaving <16>
Squares R4C9<37>, R5C7<2379>, R5C8<279> and R6C9<237> in block 6 form a comprehensive naked quad. These 4 squares can only contain the 4 possibilities <2379>. Since each of the squares must contain one of the possibilities, they can be eliminated from the other squares in the block.
R6C7 - removing <237> from <23678> leaving <68>
Squares R4C7, R6C7, R4C3 and R6C3 form a Type-3 Unique Rectangle on <68>. Upon close inspection, it is clear that:
(R4C3 or R6C3)<17> and R5C3<17> form a naked pair on <17> in block 4. No other squares in the block can contain these possibilities
R5C2 - removing <1> from <13> leaving <3>
(R4C3 or R6C3)<17>, R5C3<17> and R5C2<13> form a naked triplet on <137> in block 4. No other squares in the block can contain these possibilities
R6C1 - removing <3> from <356> leaving <56>
(R4C3 or R6C3)<17> and R5C3<17> form a naked pair on <17> in column 3. No other squares in the column can contain these possibilities
R9C3 - removing <1> from <16> leaving <6>
R7C2 can only be <1>
R9C4 can only be <2>
R9C7 can only be <1>
R8C5 can only be <5>
R2C7 can only be <7>
R2C5 can only be <1>
R7C5 can only be <6>
R3C5 can only be <7>
R5C5 can only be <2>
R5C7 can only be <9>
R5C8 can only be <7>
R5C3 can only be <1>
R7C8 can only be <2>
R4C9 can only be <3>
R7C1 can only be <3>
R3C8 can only be <9>
R8C7 can only be <3>
R8C3 can only be <2>
R7C7 can only be <5>
R7C9 can only be <7>
R4C4 can only be <7>
R6C9 can only be <2>
R4C3 can only be <8>
R3C9 can only be <1>
R3C1 can only be <2>
R1C3 can only be <3>
R1C4 can only be <9>
R1C6 can only be <4>
R1C7 can only be <2>
R3C6 can only be <3>
R3C7 can only be <4>
R3C4 can only be <6>
R6C6 can only be <5>
R4C7 can only be <6>
R6C3 can only be <7>
R6C4 can only be <3>
R4C1 can only be <5>
R6C7 can only be <8>
R6C1 can only be <6>
R4C6 can only be <1>
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