However, I do not seem to be able to move this piece, my own, with my own Jack.
Protection implies not having something unpleasant forced on you. But if I want to move my piece mostly around the board when advancing my opponent just a little, this is my choice and not my opponent's choice.
Is this by design? (My French isn't strong enough to read the French rules, which I realize the game is based on.)
Thanks for the clarification.