Had a similar problem many years back with my daughter (then aged 5) and another kid higher up the street. On a few occasions, ten minutes after going to play out, she would return, rather sullen and insist that she didn't want to play out. I came home from work one day to be shown an ugly bruise on her upper arm where this kid had hit her with an hammer. A real claw hammer, not a plastic toy! Of course i went up to see this lad's parents but there was no-one at home. So i showed my 5 year old the simple trick of putting your left foot behind a person's right heel and pushing. The very next night i had a rather irate father knocking on my door saying that my daughter had been violent toward his son - who he had with him and who was twice the size and age as my daughter. When this guy saw this and heard the full story, he literally dragged this kid back home. The lad never bullied my daughter again, nor anyone else on the street. My story perhaps illustrates what OG said earlier for i have no doubt that this lad's father (who i later found to be a decent sort) had got the anti-bullying message across to his son. Once he got over the embarrassment of having his 10yo floored by a 5yo slip of a girl, that is.