I play sword fighting with my son (now 5 3/4) on and off with wooden swords
(from Renaissance Faire and others I cut out of exterior grade plywood.) I always have him aim for the body (never the face or head). Likewise I always aim (though very light swings or stabs) at his body. He is developing a decent parry and riposte for a kindergartener. Then again dueling with a parent is one thing, hacking away at your siblings is another.

I used to fence epee and have a room with various swords hanging from the walls (high up) so I figured that my son was going to be interested sooner or later so I would teach him the basics. His sister just turned three so fencing with her is discouraged.

Panche