This puzzle belongs to the classic family of hat problems, a tradition of logic where the decisive information is not always in what is seen. The third blind wise man variant has an especially elegant twist: whoever ends up solving the problem seems to have less information than anyone else. And yet, he is the only one who can answer with certainty.
The third blind wise man
Riddle statement
Three perfectly logical wise men are sitting in a circle. The king informs them that he has five hats: three white and two black. Next, place a hat on each wise man and hide the other two. The hats are visible to the others, although no one can see theirs.
Then the king asks them in turn, always in the same order, if they can deduce with certainty the color of their own hat. The first one answers no. The second also answers no. Then the third, who is blind, answers yes.
What color is your hat?