Are you a football fan overwhelmed with the enormous quantities of unfamiliar words and phrases that comprise the football lexicon?
After listening to a press conference by a football coach with a lifetime of experience, do you feel dizzy?
Well, my friend, you are not alone.
For example, what in the world is a “3-technique”?
A “3-technique” is one of the more recent terms used to classify a pass-rushing defensive tackle.
In this article, I explore the 3-technique in further detail, delineate the prototypical traits and sizes characteristic of a 3-technique, and review the concepts of gaps and techniques.
- A 3-technique in football is a defensive tackle who lines up opposite the guard’s outside shoulder, between the guard and the tackle (the B gap).
- A 3-technique’s primary objective is to beat the offensive guard attempting to block him and penetrate the offensive backfield to disrupt the opponent’s offense.
- The most important attribute of a 3-technique is outstanding quickness.
What is a 3-Technique in Football?
(A review of techniques and gaps can be found further down in this article)
A 3-technique in football is an interior defensive lineman (defensive tackle) who lines up on the guard’s outside shoulder, between the guard and the tackle (the B gap).
In most systems, on most plays, a tackle lined up in 3-technique is supposed to shoot the gap immediately, with free rein to get upfield and create disruption. 
The 3-technique is tougher to double team simply by alignment and, therefore, can make more plays on ball carriers in the running game and get to the quarterback faster on pass plays.
3-techniques face fewer double teams because, in a typical defensive front, it aligns to the weak side (the side of the offense without a tight end) with a 5-technique defensive end outside of the weak side tackle.
This means the tackle can’t double down, and the center has a long way to go to try and execute a double team. 
The picture below shows the 3-technique defensive tackle (red box) lined up across from the guard’s outside shoulder:
What are the Most Important Traits of a 3-Technique?
The qualities most associated with the 3-technique position are quickness and explosiveness.
Defensive coordinators want their 3-techniques playing in the offensive backfield, and there is no better way to do this than with a quick first step.
Typically, the most athletic defensive interior players play this spot on passing downs regardless of their alignment on base downs. 
Who is the Prototypical 3-Technique in the NFL Today?
The answer is Aaron Donald of the Los Angeles Rams.
Donald is a three-time Defensive Player of the Year, a Super Bowl Champion, a seven-time All-Pro selection, and perhaps the most outstanding defensive player in NFL history. 
Donald, at 6-foot-1 and roughly 285 pounds, is resetting the bar for 3-technique size.
Ideal 3-techniques are smaller than other defensive tackles and significantly smaller than the guards assigned to block them.
However, their smaller size allows for the requisite quickness to beat the guard and penetrate the backfield, disrupting running and passing plays.
In a short time, Donald has changed how the league defines a “prototype” 3-technique, shaving weight and size from the previous standards in favor of speed, quickness, and leverage.
Donald is slightly smaller than former successful 3-techniques but significantly more athletic. Donald’s production on the field is dragging the league’s standards for the position in his direction. 
The below video showcases Donald’s exploits:
What Are Gaps Exactly?
Gaps are the spaces between the offensive linemen, and we label them with letters.
For example, between the center and the guard is the A-Gap, between the guard and tackle is the B-Gap, between the tackle and tight end is the C-Gap, and outside the tight end is the D-gap.
The offense wants to protect these gaps and use them as lanes the running back can run through. 
The below video addresses the gaps in the offensive line and demonstrates how Dallas Cowboys running back, Ezekiel Elliot, runs through each of them:
The defense needs to close these gaps, preventing the offense from running the ball.
Defensive Line Gap Responsibilities
Every defensive lineman will have a particular pre-snap responsibility as to which gap he is responsible for filling.
For example, say you are a defensive lineman who lines up in the A-gap prior to the snap. Your job on this run play is to clog that gap and prevent the running back from running through it.
Do you line up directly in front of the offensive linemen or shade toward one of the gaps?
This is where “technique” comes into play. 
Techniques use a numerical system to specify the position of a defensive lineman relative to the offensive lineman from which he is across. 
As a result, the numbers used to designate techniques and position defensive linemen properly are always relative to the positions of offensive linemen. 
How does the Numerical Technique System Work?
We’ve all heard a football announcer comment, “He’s a 3-technique defensive tackle.”
This is where the term originates.
In the above diagram, the yellow numbers at the top indicate the defensive lineman’s technique.
The even numbers 0, 2, and 4 designate head-up alignments – when the defensive lineman is directly in front of the offensive lineman. For example, a 0-technique defensive tackle aligns himself directly over the center, while a 2-technique defensive tackle aligns himself over the guard. 
The even numbers with an “i,” for example, 2i and 4i, indicate the defensive lineman should be opposite the inside shoulder of the offensive lineman. For example, a 4i-technique defensive end plays between the guard and the tackle in the B-gap. 
The odd numbers 1, 3, and 5 indicate the defensive lineman is opposite the outside shoulder of the offensive lineman, moving into the gap on the outside of the offensive player’s shoulder. For example, a 1-technique defensive tackle plays in the A-gap gap between the center and the guard. 
Note “inside” refers to the shoulder closer to the center, while “outside” refers to the shoulder farther from the center. 
Furthermore, we refer to any defensive lineman aligned to the inside or outside shoulder of an offensive lineman as “shaded.”
Now you know that when the announcer mentioned above mentions a 3-technique, he refers to a defensive tackle in the B-gap, shaded to the guard’s outside shoulder.