No penalty cards on the first trick — hearts and the queen of spades may not be discarded there.; Hearts cannot be led until they have been "broken" — that is, until a heart has been discarded on an earlier trick. The exception is a player holding nothing but hearts.
Why people argue about this
People often assume that hearts can be led in the first trick if they haven't been broken yet, which leads to arguments about whether a heart was played earlier or not. The confusion arises because the rule specifically states that hearts cannot be led until they've been "broken," meaning a heart must have already appeared on an earlier trick, except when you're holding no cards other than hearts.
