skip to main content




Daily Sudoku Answer 



Loading

X

Loading

Apr 16 - Super Hard
Puzzle Copyright © Kevin Stone

Share link – www.brainbashers.com/s066012



Reasoning 



R5C5 can only be <4>

R9C7 can only be <6>

R8C5 can only be <6>

R1C4 is the only square in row 1 that can be <3>

R1C6 is the only square in row 1 that can be <5>

R2C8 is the only square in row 2 that can be <9>

R8C8 can only be <4>

R8C2 can only be <7>

R7C9 can only be <9>

R9C9 can only be <5>

R8C4 can only be <5>

R8C6 can only be <9>

R1C1 is the only square in row 1 that can be <9>

R1C3 is the only square in row 1 that can be <4>

R9C3 can only be <2>

R9C5 can only be <8>

R6C3 can only be <8>

R7C1 can only be <4>

R6C7 can only be <9>

R4C3 can only be <5>

R7C4 can only be <2>

R7C6 can only be <1>

R9C1 can only be <3>

R2C4 can only be <7>

R3C6 can only be <4>

R2C6 can only be <8>

R9C4 can only be <4>

R3C4 can only be <6>

R9C6 can only be <7>

Squares R3C1 and R4C1 in column 1 form a simple naked pair. These 2 squares both contain the 2 possibilities <12>. Since each of the squares must contain one of the possibilities, they can be eliminated from the other squares in the column.

R5C1 - removing <1> from <167> leaving <67>

R6C1 - removing <2> from <267> leaving <67>

Intersection of column 8 with block 6. The values <236> only appears in one or more of squares R4C8, R5C8 and R6C8 of column 8. These squares are the ones that intersect with block 6. Thus, the other (non-intersecting) squares of block 6 cannot contain these values.

R4C9 - removing <2> from <1248> leaving <148>

R6C9 - removing <2> from <247> leaving <47>

Squares R1C7, R4C7, R1C9 and R4C9 form a Type-4 Unique Rectangle on <18>.

R1C9 - removing <1> from <128> leaving <28>

R4C9 - removing <1> from <148> leaving <48>

The puzzle can be reduced to a Bivalue Universal Grave (BUG) pattern, by making this reduction:

R4C2=<34>

These are called the BUG possibilities. In a BUG pattern, in each row, column and block, each unsolved possibility appears exactly twice. Such a pattern either has 0 or 2 solutions, so it cannot be part of a valid Sudoku

When a puzzle contains a BUG, and only one square in the puzzle has more than 2 possibilities, the only way to kill the BUG is to remove both of the BUG possibilities from the square, thus solving it

R4C2 - removing <34> from <1234> leaving <12>

R4C8 is the only square in row 4 that can be <3>

R5C8 can only be <6>

R5C1 can only be <7>

R6C8 can only be <2>

R6C2 can only be <4>

R5C9 can only be <1>

R6C1 can only be <6>

R5C2 can only be <3>

R3C9 can only be <2>

R4C7 can only be <8>

R6C9 can only be <7>

R3C1 can only be <1>

R1C9 can only be <8>

R4C9 can only be <4>

R1C7 can only be <1>

R1C5 can only be <2>

R4C1 can only be <2>

R2C2 can only be <2>

R4C2 can only be <1>

R2C5 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 setting.