Sudoku

[Sombrero]

not sure how to spell it,

but when it came out i hated it... avoided it like the plague...

attempted a few when stuck in hospital with one of my kids, then again whilst off sick from work.. now i get it, and there isn't one that can beat me now...

however, what i couldn't do, is to set one... how on earth do you set a sudoku puzzle and make it easy or hard? just beyond me !!

 

[JBR]

I'm not an expert, but I think you could say there are two stages.

The first thing would be to start with 81 empty squares and fill them in randomly, but ensure that each row and each column contain one of each number 1 to 9, and the same for each 3 x 3 square.

The second stage would be to then remove some of the numbers and, quite simply, the more you remove the harder it gets. I shouldn't leave less than, say, eighteen or it will become difficult to do even to the point of being impossible.

Then again, why bother? There are so many you could just take and use. Books full of them.

 

[Sombrero]

I'm not an expert, but I think you could say there are two stages.

The first thing would be to start with 81 empty squares and fill them in randomly, but ensure that each row and each column contain one of each number 1 to 9, and the same for each 3 x 3 square.

The second stage would be to then remove some of the numbers and, quite simply, the more you remove the harder it gets. I shouldn't leave less than, say, eighteen or it will become difficult to do even to the point of being impossible.

Then again, why bother? There are so many you could just take and use. Books full of them.

Ok, more broadly i wonder how puzzles are set so they are easy/medium/hard and not impossible to do.

Look at those crosswords where all the letters are replaced with numbers.... they have to pick key words as huge clues e.g. tete or sleeve, i just think it's a huge skill making a puzzle actually ...puzzling, and not a procedure!

I'll get my coat !!....