I've read in somebody's comment in another question:
USA Table Tennis rules: 2.5.7 A player strikes the ball if s/he touches it in play with his/her racket, held in the hand, or with his/her racket hand below the wrist. 2.5.8 A player obstructs the ball if s/he, or anything s/he wears or carries, touches it in play when it is above or traveling towards the playing surface, not having touched his/her court since last being struck by the opponent.
Does that mean that I can use my hand to hit the ball? But only my racket hand? Does that mean that when you miss the ball with the racket, but actually hits it with a finger or something it's still a valid play? Does that tell me that it's illegal to hit the ball with my free hand?
Please, don't base your answers on the interpretation of that snippet alone, maybe there are varations of this rule on other countries, for instance.