Will Shakespeare probably played blindman’s buff when he was boy.
At least he could have; the children of his day did play it, and were, perhaps, no more gentle in the sport than are some of today.
One youngster would consent to be blindfolded and attempt, then, to grab one of the other players, each of whom would push or jostle him or, especially, give him a buffet, a slap upon the rump with open hand.
And that, in the language of the period, was a buff; whence the name of the sport.