[tdb7893]

I haven't read this particular blog but the solution I remember seeing is you randomly swap the colors each edge verification so each is independent. All the edges are numbers that are required to be different so when you verify they are different you gain no information.

[jkaptur]

How does the verifier gain confidence that the prover has solved a particular instance of a sudoku puzzle?

[heinrich5991]

They can ask whether the pre-filled fields have the correct equal/unequal relationship by testing two of them at a time.