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The 4-3 defense has been one of the most popular, if not THE most popular defenses of the last 60 years. How did it develop and where did it come from?  It came from the old 6-1 that was, of course, designed to stop the run.  It featured two defensive guards, two defensive tackles, two defensive ends, and a middle linebacker. The secondary played a four deep “umbrella” scheme. Defensive guards are seldom used today, if at all. We use other terms such as tackles and nose guards but their alignment is similar to the guards in the 6-1. As offenses began throwing more (in the 1950’s), the defensive ends began to drop more into pass coverage which resulted in the 4-3. The first “official” 4-3 may have been designed by Tom Landry around 1956. In the diagram below, it’s clear to see how easy it was to drop the ends back in pass coverage to give it the 4-3 look.

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There are many reasons why the 4-3 has maintained it’s popularity.  Ask a 4-3 guy why he runs this defense and some of the common reasons you will hear are:

  • Allows you to read, react, pursue, and attack under control.
  • Great run-stopping front, with the ability to get 9 men in the box.
  • Attack type defense – makes things happen.
  • Allows linebackers freedom to go sideline to sideline in pursuit of ball carriers.
  • Designed to defeat option football. Option rules are ingrained in the defense.
  • Built in capacity to adjust and stop a variety of offenses.
  • Use of 2 safeties lets you play the pass more effectively and disguise coverages.
  • Many variations of pass coverage can be employed.
  • Generates pass rush from front four with minimal blitzing.

Naturally, there can be weaknesses as in any defense. Coaches understand the weaknesses and those possibilities are:

  • With only three linebackers, there is a liability against the passing game, especially against athletic receiving tight ends and smaller, quicker backs.
  • Soft spots or “bubbles” in the defense (open area between linemen leading to a linebacker). This is especially true on the weak side between the nose and D end. This really puts pressure on your weak side linebacker.
  • Coaches who run the 4-3 feel they need a great 3 technique tackle and an effective pass rushing D end.

Today there are teams at all levels that run the 4-3.  Youth, high school, college, and the pros can be seen every weekend playing the 4-3.  Due to the number of spread offenses that can be faced today, the 4-3 and most defenses have become all about speed on the field. The 4-3 is a speed defense as well as a spill defense, which means trying to force everything to the outside. It’s important for your secondary players to be able to come help with those plays that spill to the alley. Although there are several different ways to align and play the 4-3, the popular Miami 4-3, which was designed to stop the Wishbone in the 80’s has become what most consider the base.  It is flexible enough to be effective against the hottest spread offenses in the country. Although there are many variations of the 4-3, for this Beginners Guide we will highlight two fronts; the OVER and UNDER. Before getting into the particulars of the Over and Under, an explanation of Gap Identification and an Alignment Numbering System will be presented first.

Gap Identification is consistent with most defenses for communication. D gap, outside the tight end, is sometimes referred to as the Alley. For our purposes we will use either term.


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Alignment Numbering System

The alignment numbering system, commonly known as alignment technique, is very important for quick communication between coaches and coaches to players. This tells the players where to align. There are many numbering systems and all coaches are free to use their own method.  For our purposes we will use the most common system shown below.

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As with any defense, the question of “who plays where” must be addressed. That is based on what position is being played. In general, the four defensive linemen should be big strong kids that can take on offensive linemen. If they can also show quickness and run well, that’s a plus, especially against today’s spread offenses. The three linebackers should be some of your best, most aggressive defenders. These kids just love to hit and seem to have a knack for making tackles. Usually quicker and faster than defensive linemen, these guys are considered the heart of the defense. The secondary consists of two corner backs and two safeties. The corner backs (corners) should be able to cover wide receivers, which means they must be fast. They can be viewed as “fighter planes” in your Air Force. They are fast, agile, able to change directions, and maneuver quickly. Size is not as important as the ability to cover. They will be asked to come up and support the run also, so the ability to make tackles in the open field will make them more valuable. Safeties are like a hybrid between linebackers and corners. It’s essential they be able to give strong run support, especially in the Alleys. They also must have the speed to cover receivers and large areas of zone coverage. Many coaches consider safeties their best athletes on defense. Overall, the eleven positions should be filled with tough, aggressive kids that can move!

The next question that arises is, “do we want to have a strong side and a weak side”? Otherwise known as flip – flopping the defense. The strong side is the side with the tight end or the most receivers. In today’s defenses, most teams DO have a strong side and weak side, but it’s not essential. That is a coach’s decision. Because of the way defenses have evolved, it is recommended to have a strong/weak side system. That allows you to match the offense strength with strength.

 4-3 OVER

Shown below is a diagram of the 4-3 OVER defense. It is a “cover 2” which means each safety has a deep half. Below the diagram will be alignment and assignment responsibilities along with recommendations for player capabilities.

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Alignment, Assignment, vs Run 

Strong Side End – Align in a 9 technique outside shoulder of Tight End. If no TE align in a 5 technique. D gap or C gap responsibility. Biggest, strongest of the D ends.

Weak Side End – Align in a 5 technique outside shoulder of Weak Side Tackle. C gap responsibility. Usually faster and quicker than strong end.

Strong Side Tackle – Align in a 3 technique outside shoulder of Strong Guard.  B gap responsibility. He should be your very best defensive lineman.

Nose Tackle – Align in a 1 technique on weak side of Center. A gap responsibility. Second best D lineman and they come in all sizes. Can be a big kid that plugs the gap or a smaller, quicker kid that wreaks havoc.

Mike Linebacker – Best linebacker over the strongside A gap. Should be physical enough to take on lead blockers. Flow strong – strong A gap. Flow weak – weak B gap.

Sam Linebacker – Second best linebacker aligns over C gap, outside shoulder of strong tackle. Flow strong – strong C gap. Flow weak – check cutback.

Will Linebacker – Align over the weak side B gap. Free to roam a little. Check B gap on flow to; be ready to go to alley on spill.

Safeties – Base coverage is deep half to their side. Strong Side Safety (SS) should be your best run support guy of the two safeties. Free Safety (FS) more of a cover guy. Run responsibility is A gap to alley/contain. Remember, these two guys are probably your “supermen”.

Corners – Base coverage is outside flat. Run responsibility is support on flow to; flow away, check counter/reverse then pursuit angle.


Next, is pass assignment responsibilities (shown below). These are the pass assignments for “cover 2” which, as you remember, means the two safeties  are responsible for the 2 deep zones. However, note that the middle linebacker (Mike) has the “high hole”. He will be responsible for the hole between the safeties. So, admittedly, it looks a little like cover 3 (three deep players). There are many different coverages  that can be played and there are many resources here on Chiefpigskin.  To learn how to be multiple in your coverages we suggest checking out these videos by Jake Gilbert of Westfield HS, IN.  To learn cover 2 read or “Palms” (which is the most common collegiate coverage) check out these videos by Tre Stewart of Illinois College.


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Pass Assignments

Defensive Line – Get into pass rush technique. Ends maintain outside leverage and keep contain on QB. Tackles get up field and keep gap lane responsibility.

Mike Linebacker – High hole middle 1/3.

Sam and Will Linebackers – Drop to curl looking for #2 receiver.

Free and Strong Safety –  Deep 1/2.

Corners – Press coverage to flat #1 receiver.



In the 4-3 Under Front  the defensive line shifts to the weak side of the offense. Many coaches feel the Under Front is stronger against the run than the Over because there is one less “bubble” in the front with 5 players on the line instead of 4. At any rate, it gives the offense a different look and is easy to adjust to for the defense. How many fronts, coverages, blitzes, etc. should a defense have? Again, that’s up to the coaching staff. At the lower levels of football, learn one front, one coverage, and do it well. When you as a coach feel your players are ready for more, add more. Most coaches want their defenders to know a simple defense to avoid confusion. “Play fast” is the term we use and that can only be done when the players are confident of their responsibilities. In this Under Front the Sam Linebacker moves up to the line of scrimmage in a 9 technique which gives a 5-2 look ( 5 linemen and 2 linebackers). Sam now has force, contain. The Nose shifts to the strong side of the center and is now in a strong 1 technique. The Tackle moves to the weak side in a 3 technique. Mike now has strong B gap and Will has weak A gap.


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Alignment, Assignment, vs Run & Pass

Strong Side End – Align in a 5 technique on strong side tackle. C gap on run and pass rush in lane when reading pass.

Weak Side End – Align in a 5 technique. C gap on run and outside pass rush.

Strong Side Tackle – Align in a 3 technique on weak guard. B gap on run and inside pass rush.

Nose – Align in a 1 technique to the strong side of the center. A gap on run and inside pass rush.

Mike – Align over strong side guard. Flow to, B gap. Flow away, weak side A gap. Hook zone on pass.

Sam – Align in a 9 technique on LOS. Force, contain on run and curl on pass.

Will – Align stagger stacked behind D tackle and A gap to alley on flow to. Flow away, A gap for cutback. Curl on pass.

Corners – Press coverage to flat # 1 receiver. Run support on flow to, flow away, check counter/reverse then pursuit angle.

Safeties – Run support A gap to alley and deep half on pass.


Being Multiple

Learning the  Over and Under fronts with a two deep coverage is a great starting place for the 4-3 defense. But let’s face it, you’ve really got to have more fronts and coverages to be effective. That’s whats called being multiple. For example, what if its 3rd and less than a yard? Do you have a front for that? Or what about 3rd and 12 and your opponents have a play that they’ve been torching you with? Many times your opponent might have a star player that requires special attention and a different coverage, or maybe you are facing an opponent where you need more run support. In the example below, your opponent is in a power run formation to the strong side. You may want to move your Strong Safety up to a linebacker position and match their strength. If the Sam linebacker squeezes down on a down block from the TE and spills the play to the alley, the Strong Safety is in perfect position to make the play. Behind this front a Cover 3 (3 deep) can be played with the FS and corners. It comes down to a chess match – if they do that, we do this.

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Jake Gilbert, Head Coach Westfield High School

Jake Gilbert, Head Coach Westfield High School

The best we know at being multiple with the 4-3 is Jake Gilbert, head coach at Westfield High School in Indiana. A former Defensive Coordinator at Wabash College, Gilbert has been the head coach at Westfield since 2010. Since 2013 his teams have gone 38-14, capping it off with a 5A State Championship in 2016. I first saw Coach Gilbert at a Glazier Clinic in Indianapolis this past winter and knew immediately that his Multiple 4-3 was on the cutting edge of high school defense. Coach Gilbert not only has different ways to play Cover 2, but also has change ups to Cover 0, 1, 3, and 4. In addition, they can play with  3, 4, or 5 down linemen to adjust for every opponent on their schedule and adjust to every player or situation.  If you’re a 4-3 guy or thinking of switching to the 4-3, we highly recommend Coach Gilbert’s Shamrock 4-3.


We here at Chiefpigskin believe that all defenses are good if learned inside and out and then taught to your players inside and out. The 4-3 is no different and the available videos will give you that opportunity.

As always, feel free to contact us here at Chiefpigskin any time to talk football. That’s what we do.

Coach L. Albaugh     DBLITY