The New Sudoku Players' Forum

[John H]

the grid for 19th Jan is marked as 'easy' but i think it's impossible. I believe the square marked 'a' has to be both 3 and 5

. 2 6 | . . a | . 7 1
. 5 9 | . 8 . | . . 6
4 . 1 | . . 9 | 2 . .
------+-------+------
. . . | . . 3 | . 9 .
. 8 7 | 5 6 4 | 1 2 .
. 4 . | 7 . . | . . .
------+-------+------
. . 2 | 3 . . | 8 . 9
1 . . | . 5 1 | 6 3 .
3 7 . | . . . | 4 5 .

[vidarino]

the grid for 19th Jan is marked as 'easy' but i think it's impossible. I believe the square marked 'a' has to be both 3 and 5

Code: Select all

. 2 6 | . . a | . 7 1
. 5 9 | . 8 . | . . 6
4 . 1 | . . 9 | 2 . .
------+-------+------
. . . | . . 3 | . 9 .
. 8 7 | 5 6 4 | 1 2 .
. 4 . | 7 . . | . . .
------+-------+------
. . 2 | 3 . . | 8 . 9
1 . . | . 5*1*| 6 3 . <- two 1s
3 7 . | . . . | 4 5 .


There is an error in that grid. The 1 in R8C6 seems to be out of place, as it conflicts with the one in C1 on the same row. Removing it makes the puzzle solvable with singles only.

Vidar

[Animator]

The 1 in r8c6 is indeed incorrect.

(You can tell which one of the two is incorrect by looking at the symmetry of the puzzle. r2c9 has a number; r2c4 hasn't.)

[Crazy Girl]

i believe this should be the correct puzzle, if you paste the puzzle into a solver without R8C6=1, then you get an 'easy' solution

Code: Select all

 . 2 6 | . . . | . 7 1
 . 5 9 | . 8 . | . . 6
 4 . 1 | . . 9 | 2 . .
-------+-------+------
 . . . | . . 3 | . 9 .
 . 8 7 | 5 6 4 | 1 2 .
 . 4 . | 7 . . | . . .
-------+-------+------
 . . 2 | 3 . . | 8 . 9
 1 . . | . 5 . | 6 3 .
 3 7 . | . . . | 4 5 .