Just hard enough to make the ref and the judges think he's doing damage, but not hard enough to actually hurt any fighter worth a lick.
does a fighter have to be damaging his opponent every time he punches him? does it take away from fighters like sweet pea for instance who would land the leather but not always be inflicting damage on his opponent?
He mixes up the power of his shots. He can definately hurt you. This slapping thing just keeps his opponents in la-la land and off balance and normally in those flurries theres a hard shot to the body or head in there
His hands have become more of an issue as the years have gone by, that's why most had Lacy down to beat him. If you watch footage of him from his early days as WBO Champion he was heavier handed, still fighting the same style with flurries of slaps with the odd meaningful blow here and there but he seemed to hurt tough opponents much more back then. He still made a mess of Jeff Lacy's face and hurt Kessler to the body so he obviously doesn't merely dupe referees and judges the way K0NPHL1C7 is suggesting.
Awesome KO record for much of his career, definitely not hitting nearly as hard now, but certainly hard enough.
They don't call him "slappy" Joe for nothin! Maybe half his 1000 punches are slaps with the other half comprised of medium power punches.