“An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force.”


Isaac newton’s First Law of Motion, aka, The Law of Inertia



R2D2  is an arm control I invented that is good for intervening to protect others from an unarmed or even an armed Badguy.



R2D2 works on three principles, aka, The 3 Laws of R2D2


1- If the Badguy is focused on his victim, you can flank him. (Tunnel Vision Rule)

2- The Law of Inertia is on your side. (Inertia Rule)

3- Any R2D2 (meaning any way you grab the rear arm) is a good R2D2 as long as you can transition into a better arm control (like Cop’s Russian). (Transition Rule)



Breaking It Down


1st Principle

R2D2 is not so much a self-defense technique but a technique for defending others.  This is because R2D2 requires you to flank, get around, the Badguy.  If you can’t flank the Badguy you can’t R2D2.

But, if you are in the act of protecting somebody else you can almost always flank the Badguy.  That’s because the Badguy’s attention is on his victim.  In NYPD, we call this “tunnel vision”.


2nd Principle

There are two categories of R2D2’s, Moving R2D2’s and Still R2D2’s. Most weapon attacks against victims are Moving R2D2’s and the inertia is stronger with Moving R2D2’s. 

Because the Badguy is already in motion, once you grab them from an angle they will often take themselves down.  This is because the Badguy will be off-balance enough before you touch him to take himself down after you touch him.  That’s why The Law of Inertia works for you and against the Badguy.

With Still R2D2’s it’s more complicated and you need to “trick “ the Badguy into giving you inertia.  I talk about that on my Calm Down Sir page.



3rd Principle

Because of the 2nd Principle, The Law of Inertia is on your side, any R2D2, meaning any rear 2-on-1 (grabbing wrist and shoulder, wrist and elbow, elbow and shoulder, etc) is a good 2-on-1 as long as you can can transition into something better if the Badguy doesn’t fall down right away.  Practicing this transitioning in training is an insurance policy in case things don’t go according to plan

Transitioning from weaker arm controls into stronger arm controls is a big part of the art of The Outer Clinch and I write more on that in my article on R2D2 combinations.


The attached video, is a demonstration of my Moving R2D2 Arm Control, which I used to save life number 3 on a New York City subway and for which I received a medal and commendation. Ali Al-Abad, who plays the Badguy with the knife, had prior tae kwon do training and Jon Hasan, who plays the Goodguy with empty hands, had no prior martial arts training.




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