Where are the difficult sudoku puzzles with very few numbers in them?

I put the tag sudoku but it is not there

A sudoku puzzle must have a unique solution.
The minimum number of clues required to fulfill that rule, is 17.

I don’t know what a unique solution means in this case.
But I hardly do them, but I have seen some with less than 17.

unique means that there can only be one solution to a puzzle.

@ragingloli Of course there can only be one solution to a puzzle. Why would that need to be said?

@flo
because if a puzzle has less than 17 clues, there will be more than 1 solution to it.

I’m reading the explanation, in your link. Over my head.

I just remember many years ago, seeing some with maybe 10 clues. I guess it is less complicated if there is one solution.

The detail part of the OP has been edited by the way.

It needs a minimum number of clues, I get it now.

There are two sources of difficult puzzles which meet the requirement of a unique solution.

For physical paper books, Will Shortz has published several at all difficulty levels including the hardest.

If you’re unfamiliar with him, he is the crossword editor for the New York Times and a llifelong self-professed gaming fanatic. He doesn’t just limit himself to crossword puzzles but Sudoku as well.

For digital puzzles, there are two IOS apps which I use daily and you can choose the difficulty level you prefer.

The first one is Sudoku Daily.

The next is Sudoku 101 and the a more advanced one. I’ll look up the developer listed for each of these and edit it back in so you’ll be sure to get the correct ones.

There are SO MANY Sudoku puzzle apps with quite similar names and I’ve probably tried most of them but these are 2–3 of the best, in my opinion.

The Sudoku Daily app is created by Phase 2 Media

Sudoku 101 is published by River Past Media and more info is available at
www.sudobility.com

Another good feature of Sudoku 101 is if you’re stuck, you can switch over to the “teach me” option. This will take you step-by-step to the solution so that you can learn what you’ve overlooked. I really appreciate this feature and have learned so much from it.

A separate app with higher difficulty levels from this same company is Sudoku 401. It also contains the same teaching feature.
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ALSO: available for both IOS and Android are several apps published by Jason Linhart which also have an excellent reputation.

Have you tried Ken-Ken? The puzzles are similar to Sudoku, except there’s math involved. Each number appears just once in any row or column, and the numbers within a cell need to satisfy an arithmetic function. I find Ken-Ken more challenging, and more interesting, than Sudoku.

All my life I’ve been in the category of those who are “math challenged” so it’s unlikely that Ken Ken would be something I find enjoyable.

The reason I like Sudoku is because, even tho it involves numbers, it isn’t about math.

It’s really about pure logic. The numbers are just symbols to put in the squares. You could substitute anything for the numbers such as pics of nine different flowers or nine different animals. (and I’ve seen Sudoku puzzles like that.)

But the main problem is that it takes so much longer to do them because trying to figure out which flowers are still needed in a particular row or column is more difficult to remember. But numbers are much easier to spot because their consecutive order is the same and we can rembrr it in our minds without needing to constantly look at a chart, like with different type of pictures.

@Buttonstc Well, I have to confess that I exaggerated when I said “math.” It’s really arithmetic. Ken-Ken has addition, subtraction, multiplication, and division, but nothing more. It encompasses the logic of Sudoku with a slight twist.