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The basics of defensive alignment

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A beginner’s guide to identify gaps and defensive alignment.

NCAA Football: Lamar at Houston
Todd Orlando, Houston Cougar’s defensive coordinator and interm head coach may join Tom Herman in Austin.
Erik Williams-USA TODAY Sports

Earlier this afternoon, I started to write an article about what the Texas Longhorns defense will look like under Tom Herman. Based on what Todd Orlando, Herman’s defensive coordinator did at Houston, and the fact that Herman has stated in the past that he prefers the multiple 3-4 defense, I decided to preview this defensive scheme.

Then I noticed the article was extremely confusing. The more I wrote, the more I realized that there are certain terms that must be discussed before we can get into details.

These terms are fundamental terms to a football coach (or player) just like the words tackle, hand off, block, and well you get the picture. Before we can start discussing the Tampa 2, and what an eagle or stack front is, we must first establish a certain fundamental communication.

The most important part of this communication is where the player starts the play, or alignment. Many TV announcers talk about the 5 or 7 technique and how it affects the offenses blocking strategy, but what exactly does that mean.

The number system in the linked diagram shows how defensive alignments are numbered and how gaps are identified. While offenses often identify gaps with even numbers to the right and odd numbers to the left, the defensive system splits the field at the center, and uses a mirror image technique. Even numbers indicate a head up position as follows:

Head up on the center is called a zero technique. Head up on the guard is a 2 technique, the tackle is a 4, and the tight end is a 6. Head up on a wing back would be an 8 technique.

Odd numbers indicate a shade. A 1 technique is a shade technique on the center. A 3 is an outside shade on the guard. A 5 is on outside shade on the tackle.

Okay now bear with me, this is where it gets weird. There is no number technique for an inside shade on the tackle. This technique is referred to as an inside 4 or a 4i. This is likely because using a 4i technique puts the defensive lineman in a vulnerable position, and is rarely used for that reason.

A brilliant offensive line coach once told me “only an idiot uses a 4 technique.” The same could be said for a 4i, but I am sure there are coaches out there who are smarter than me using both of these techniques.

So back to the numbering. Using an inside shade on a tight end is a popular technique, so it has its own number, 7. An outside shade on the tight end is a 9.

These techniques can be applied to linebackers as well by adding a zero, creating a two digit number. For example, a 00 would be a linebacker position (3-5 yards from the line of scrimmage) head up on the center and a 30 would be a linebacker with an outside shade on the guard.

The gaps are lettered starting with the center/guard gap, the A gap. The guard/tackle gap is the B gap, tackle/tight end C gap and outside the tight end is D gap. This relates to defensive responsibilities that are associated with the alignments.

For example, a linebacker lined up in a 30 technique would have B gap in a base defense, although he could have A or C gap depending on line stunts and how the defensive line is aligned. A 00 would likely have double A gap responsibilities, but that can also vary based on a number of details.

So now that we have established a base of communications for how a defensive front can be number and responsibilities can be lettered, we can get into the details of the multiple 3-4 defense that Herman prefers. We can talk about a 3 technique stunting into the A gap and hopefully no one will be confused.

Look forward to more detail analysis like this in future posts.