Mar 15 - Very Hard
Puzzle Copyright © Kevin Stone
Share link – www.brainbashers.com
Reasoning
R4C6 can only be <1>
R8C9 can only be <6>
R4C4 can only be <5>
R4C3 can only be <6>
R4C7 can only be <9>
R6C4 can only be <4>
R5C5 can only be <6>
R5C2 can only be <5>
R6C6 can only be <2>
R6C7 can only be <5>
R6C3 can only be <3>
R5C8 can only be <1>
R5C3 can only be <8>
R1C2 can only be <4>
R5C7 can only be <2>
R9C2 can only be <7>
R3C2 can only be <3>
R7C2 can only be <6>
R3C7 is the only square in row 3 that can be <6>
R7C8 is the only square in column 8 that can be <9>
Intersection of row 1 with block 3. The value <8> only appears in one or more of squares R1C7, R1C8 and R1C9 of row 1. These squares are the ones that intersect with block 3. Thus, the other (non-intersecting) squares of block 3 cannot contain this value.
R3C8 - removing <8> from <458> leaving <45>
Intersection of row 9 with block 9. The value <8> only appears in one or more of squares R9C7, R9C8 and R9C9 of row 9. These squares are the ones that intersect with block 9. Thus, the other (non-intersecting) squares of block 9 cannot contain this value.
R7C7 - removing <8> from <3478> leaving <347>
R8C7 - removing <8> from <348> leaving <34>
R8C1 is the only square in row 8 that can be <8>
R8C3 is the only square in row 8 that can be <9>
R3C1 is the only square in row 3 that can be <9>
Squares R3C4<18>, R3C5<145>, R3C6<48> and R3C8<45> in row 3 form a comprehensive naked quad. These 4 squares can only contain the 4 possibilities <1458>. Since each of the squares must contain one of the possibilities, they can be eliminated from the other squares in the row.
R3C3 - removing <15> from <1257> leaving <27>
R3C9 - removing <5> from <257> leaving <27>
Intersection of row 3 with block 2. The values <18> only appears in one or more of squares R3C4, R3C5 and R3C6 of row 3. These squares are the ones that intersect with block 2. Thus, the other (non-intersecting) squares of block 2 cannot contain these values.
R2C5 - removing <1> from <145> leaving <45>
Squares R2C5 and R2C7 in row 2 and R8C5 and R8C7 in row 8 form a Simple X-Wing pattern on possibility <4>. All other instances of this possibility in columns 5 and 7 can be removed.
R3C5 - removing <4> from <145> leaving <15>
R7C5 - removing <4> from <134> leaving <13>
R7C7 - removing <4> from <347> leaving <37>
R9C7 - removing <4> from <48> leaving <8>
R1C7 can only be <1>
R1C3 can only be <5>
R1C8 can only be <8>
R9C3 can only be <4>
R2C1 can only be <2>
R7C1 can only be <5>
R3C3 can only be <7>
R3C9 can only be <2>
R2C3 can only be <1>
R7C9 can only be <7>
R7C7 can only be <3>
R2C9 can only be <5>
R9C8 can only be <5>
R7C3 can only be <2>
R3C8 can only be <4>
R2C5 can only be <4>
R3C6 can only be <8>
R2C7 can only be <7>
R7C5 can only be <1>
R8C7 can only be <4>
R8C5 can only be <3>
R3C4 can only be <1>
R7C6 can only be <4>
R7C4 can only be <8>
R3C5 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 setting.