Fewest given numbers to solve a Sudoku

What is the fewest number of given numbers you would need to solve a Sudoku puzzle?

This article in The Scientific American discusses a number of issues relating to Sudoku, including the one asked in the OP.

It doesn’t tell us unless we subscribe. Can you summarize? Please?

IIRC (the magazine’s in my friend’s apartment at the other end of the country), the “best guess” now is that 16 or 17 is the minimum clue set. Every time the researchers tried one less clue, it was impossible to solve.

My first thought on reading the OP was, “Zero.” Put in the numbers any way you like, as long as they follow the rules (I’ve never played, but I get the general idea). Unless we’re specifying that a specific arrangement of numbers is the desired result.

How about the fewest number of starting numbers such that there is a single correct solution.

Oh, well that’s very different. Never mind.
</Emily Litella>

Per the Scientific American article that I have in front of me. The current lowest is 17 numbers. With 16 they get 2 valid results for a puzzle. The problem is still being worked on.

I am glad our tax dollars are being put to good use. Makes a change from that nonsense about curing cancer :slight_smile: