If you haven’t used your forearm for striking, you are in for a pleasant surprise. It’s easy to deliver, hard to block and causes a world of pain to the victim.

Inside and Outside Forearm Strikes

Let’s call the thumb side of your forearm the “inside” and the little finger side the “outside” forearm. Both are used to deliver painful strikes to your opponent’s vulnerable targets—head, neck, ribs and groin—and to less vulnerable ones like the chest, back, upper arms and thighs. While the latter targets are not as susceptible to pain and debilitation as those in the first grouping, you can still hit them to cause momentary distraction so you can get to the more vulnerable ones.

Striking with the inside of the forearm is similar to throwing a roundhouse punch and striking with the outside of the forearm is a similar motion to the backfist. When striking with either side, it’s imperative that you keep your arm bent to prevent injury to your elbow joint. Here are three ways you can practice forearm strikes in the air and on a bag.

Face your imaginary opponent in your fighting stance. Step forward and drive a right reverse punch into his chest, followed by a left elbow to his ear. Whip your right arm around behind his head and snap the inside of your forearm into the back of his skull. He can’t defend against the elbow because he can’t see it. Work to make the combination flow smoothly.

Air: 3 sets, 10 reps – both sides
Bag: 3 sets, 10 reps – both sides

Forearm to nose

Face your imaginary opponent in your fighting stance, left leg forward. He throws a reverse punch that you slap to the right with your lead hand, but he continues to move forward, and before you can retract your blocking hand so as to backfist him, he is too close. No problem, you still have the outside of your forearm, which you ram into the point of his nose.

Air: 3 sets, 10 reps – both sides
Bag: 3 sets, 10 reps – both sides

Forearm to groin

You and your imaginary opponent are exchanging a series of blows and blocks. You lose your footing and go down on one knee in front of him. He moves in for the kill but you are too quick for him as you snap your forearm up between his legs.

Air: 3 sets, 10 reps – both sides
Bag: 3 sets, 10 reps – both sides

Hacksaw forearm

The first time I experienced this little goodie, I didn’t know it had a name, but I did know that it hurt. I was training in jujitsu with Professor Tim Delgman at his San Francisco school, and he was doing a move on me in which he slid his forearm along my neck. After a half dozen reps, my baby-soft skin was bleeding from the abrasions caused by the rough sleeve of his judo gi.

When I mentioned it to him (I may have whined), he said that he was actually being kind and just barely skimming along my skin. He then did the technique the way it was supposed to be done with lots more pressure against my neck from his forearm. Not only did it hurt more, it turned me 90 degrees away from him.

Since I enjoyed that so much, he showed me a variation where he slid his forearm along my face. This time I spun even further around, which made it a piece of cake for him to apply a follow-up grappling hold.

The next time I saw the technique was in a book called Indonesian Fighting Fundamentals: The Brutal Arts of the Archipelago by Instructor Bob Orlando, who teaches an eclectic mixture of Chinese kuntao and Indonesian pentjak silat. In his system, he teaches a principle called “adhesion” where instead of knocking your opponent away from you, which gives him an opportunity to come back fighting, you remain virtually stuck to him so that you can easily finish him off with additional blows.

One method of applying adhesion to an opponent is to use the forearm rub Professor Delgman used so painfully well on me. Orlando calls it “hacksaw” saying that it’s characteristic of pentjak silat. In his book, he says that the hacksaw motion neither chops like an axe nor cuts like a saber. “...it saws through the target using a combination of lateral and forward motion,” he writes. “[A real hacksaw] works not by simply skimming across or gliding over the object it is to cut. It presses into the object as it is pushed along.

Bob Orlando explained one method of using the hacksaw against an opponent’s head. “I often use the hacksaw on my opponent’s head or neck to cause his head to turn away. Rotating his head rotates his body, while a direct blow often sends him back, but with his fists and feet still trained on me. Rotating my attacker and hacking through his head, neck, or shoulders are some of the very best ways to keep him within range and under my control. I say ‘my control’ because he reacts pretty much the way I expect (read: dictate) him to react. By turning his ugly head, I also turn his hands and feet away from me. Moreover, I prevent him from seeing, and possibly countering what I’m going to do next. The hacksaw allows me to stick to my opponent, direct his motion, and remain in position to dissuade him from his self-destructive actions. A similar blow to the head (without the adhesion inherent in the hacksaw) may knock him down, but then I’ll have to run the gauntlet of his legs to secure a similarly advantageous position.

Hacksaw is a little tricky to practice alone. You can do it on an imaginary opponent as long as you can create and maintain a clear image of his reactions to what you are doing. You can also do it on a bag to get a general feel for the sawing motion. Here is a simple combination you can practice in the air and on a bag to get you thinking of other ones.

Kick, hacksaw and knee strike the air

Face your imaginary opponent with your left leg forward. Kick his forward knee with a right scoop kick (“Scoop kick”, page 54). He will react by bending slightly, or a lot, over his kicked knee, which will position his head a little closer to you. Shoot your right forearm to his face and hacksaw it along his features. The sawing motion will turn his head to his right. Cup his eyes with your right hand and thrust a left scoop kick into his other knee.

2 sets, 10 reps – both sides

Kick, hacksaw and knee strike the bag

This works best with a manikin, but you can make do with a regular hanging bag. Face the bag and kick the air as if hitting your opponent’s knee. Set your foot down in front and shoot your right forearm across the face of the bag, cup it with your palm and drive a knee strike into it.

2 sets, 15 reps – both sides