Today I released an amazing -wonderful new type of sudoku that reader Alf Smith invented. Like all sudoku, numbers from 1 to 9 should appear in all rows, columns and boxes.
What is different from this new variant, however, is that the starting grids have no hints of the number. Instead, some cells are gold -colored. Excessive rule is the numbers in gold cells should describe the position of that cell in either row, column or box (read left-right, top-to-bottom.)
I’ll take you through a 6×6 tutorial, so you got the hang of it. (There are two 9×9 puzzles after. To print all three puzzles click here for a PDF.)
1.
A number in a golden cell describes its position in either row, column or box. Thus, in the top left box, the gold cell in the first column should be either a 1 (position 1 in the row), a 2 (position 2 in the column) or 4 (position 4 in the block). I added possible numbers to gold cells to the top two rows in the illustration below. To be clear about the cell positions in the box, they run 1-2-3 in the first row, and 4-5-6 in the second.
OK, lets start:
Step 1. All columns contain each digit, so there is a 2 in the second column. It should go to the golden cell, because if it goes into a white cell it will describe its position as 2 in the row, which is prohibited. (If a number of position describes, the cell should be gold.) Also, 4 in column 4 can only go to the golden cell.
Step 2. The 4 (marked red) in row 6 can only go to column 6. It cannot go to a golden square in row 6, because none of the gold squares are in the 4th position. And it can’t go to the other white squares in row 6, as these squares are in the position of box 4, which means the number describes its position, which is prohibited for white squares.
What I like about these puzzles is that solving requires you to think not only what you can put in cells, but also you can’t.
Step 3. In column 6, I placed all the possible numbers that could go to gold cells. Since there are 4 rows 6, the cell in row 4 should be 6 (marked red), and then in row 2 should be 2 (again red). The row 5 should be either 3 or 5. We provide it should be 3, as the only other free space in the column is white, in the position of box 3, which will provide a contradiction.
That’s enough help! Now to you.
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3.
I will return to 5pm UK with the solutions. PLEASE NO SPOILERS.
Here is the link to print them all again.
Alf calls his puzzles to be POSIDOKU. I think there may be a catchier title, says Clueless Sudoku, or Golden Sudoku? Add your ideas below! Let’s do this puzzle that is a classic.
I’ve set a puzzle here on alternate Monday since 2015. I’ve always been out for great puzzles. If you want to suggest one, email me.
