Thanks, everyone!
My son was just playing chess with a friend from down the street...and, the young boy never called "check"...and, in the next move physically took my son's king. My son immediately said, "You never said 'check." And, the other child continued to argue that he didn't have to say it and he won. He told me that's the way he plays all the time. I thought it might be some kind of rule I had never learned. I tried to explain to him that he was not correct...but, to no avail. HA!!
Smiles!
~Holly