“Silly” or not, this is another great game, and I thank you for it. This is probably my favorite of those “silly random games” of yours yet.
Truth be told though, the game is fairly easy if you’re “only” focusing on winning. When you’re attacking, stab. When you’re defending, block middle so the enemy can’t stab.
There’s no other place either of you can hit to do more damage. So just keep up a constant defense and attack around there. On top of that, the other middle-attacks are useless since they’re blocked by the same thing as a stab, so even if it works and you get through you’ll just do a third of what you could’ve done.
Getting a no damage run would be more daunting. Still, kudos!