The full reasoning can be found below the Sudoku.
Mar 02 - Hard
Puzzle Copyright © Kevin Stone
Reasoning
R1C4 is the only square in row 1 that can be <6>
R2C9 is the only square in row 2 that can be <5>
R5C4 is the only square in row 5 that can be <3>
R5C6 is the only square in row 5 that can be <8>
R6C2 is the only square in row 6 that can be <3>
R8C2 is the only square in row 8 that can be <8>
R9C3 can only be <7>
R1C3 is the only square in row 1 that can be <8>
R2C8 is the only square in row 2 that can be <8>
R9C9 is the only square in row 9 that can be <3>
R9C1 is the only square in row 9 that can be <6>
R9C5 is the only square in row 9 that can be <8>
R9C7 is the only square in row 9 that can be <5>
Squares R8C7 and R9C8 in block 9 form a simple naked pair. These 2 squares both contain the 2 possibilities <29>. Since each of the squares must contain one of the possibilities, they can be eliminated from the other squares in the block.
R7C9 - removing <9> from <179> leaving <17>
R8C8 - removing <29> from <1279> leaving <17>
Intersection of row 2 with block 2. The value <2> only appears in one or more of squares R2C4, R2C5 and R2C6 of row 2. 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 <12> leaving <1>
R3C6 - removing <2> from <1249> leaving <149>
Squares R4C5 and R6C5 in block 5 form a simple naked pair. These 2 squares both contain the 2 possibilities <25>. Since each of the squares must contain one of the possibilities, they can be eliminated from the other squares in the block.
R4C4 - removing <25> from <2457> leaving <47>
R4C6 - removing <2> from <12467> leaving <1467>
R6C4 - removing <25> from <2457> leaving <47>
R6C6 - removing <2> from <12467> leaving <1467>
Squares R4C4 and R6C4 in column 4 form a simple naked pair. These 2 squares both contain the 2 possibilities <47>. Since each of the squares must contain one of the possibilities, they can be eliminated from the other squares in the column.
R2C4 - removing <4> from <249> leaving <29>
R7C4 - removing <7> from <579> leaving <59>
R8C4 - removing <7> from <2579> leaving <259>
R7C9 is the only square in row 7 that can be <7>
R5C9 can only be <4>
R8C8 can only be <1>
R5C1 can only be <7>
R6C7 can only be <2>
R6C5 can only be <5>
R8C7 can only be <9>
R4C9 can only be <9>
R8C1 can only be <5>
R1C7 can only be <4>
R9C8 can only be <2>
R9C6 can only be <9>
R3C8 can only be <9>
R3C6 can only be <4>
R1C9 can only be <2>
R4C5 can only be <2>
R8C4 can only be <2>
R8C6 can only be <7>
R2C4 can only be <9>
R7C4 can only be <5>
R1C1 can only be <9>
R3C9 can only be <1>
R2C2 can only be <1>
R2C6 can only be <2>
R3C1 can only be <2>
R1C2 can only be <7>
R7C1 can only be <1>
R2C3 can only be <4>
R4C2 can only be <5>
R7C2 can only be <9>
R4C3 can only be <1>
R4C6 can only be <6>
R6C1 can only be <4>
R4C8 can only be <7>
R6C6 can only be <1>
R4C4 can only be <4>
R6C8 can only be <6>
R6C4 can only be <7>
Today's Sudoku Puzzles
All daily items change at midnight GMT. set time zone