history of the 1-gap 3/4 defense

from Guide to N.F.L. Defenses, Part 4: The 3-4 Front

https://fifthdown.blogs.nytimes.com/2010/09/09/guide-to-n-f-l-defenses-part-4-the-3-4-front/

Bum Phillips and the 1-gap 3-4

To hear Bum Phillips tell it, developing his version of the 3-4 defense wasn’t rocket science.

“Coaching is pretty simple really. If you don’t got something, find something you do got. Really, we didn’t have but one [defensive lineman] – [Hall of Famer] Elvin [Bethea] – until we got Curley [Culp] in the middle of that season. Then we had two. What we did have was four real good linebackers, so all I done was find a way to get our best players on the field.”

Like the Fairbanks-Bullough 3-4 scheme that was taking hold in New England at the same time, Phillips was looking to contain the run and create mismatches in pass rush. Though Phillips based his scheme on the same concepts that the New England coaches did, he favored a more attacking style. He used a number of one-gap techniques in his front seven, stunting and slanting his linemen to cause pressure and using an OLB – “Dr. Doom” Robert Brazile, who was LT before Lawrence Taylor came into the league – frequently as a fourth pass rusher. In many ways, Phillips’s scheme was a 4-3 with four players in a two-point stance.

That attacking style of play has stood the test of time better than the read-and-react style for much the same reason that the 4-3 with an under or over shift has. It allows players to attack the offense, specifically by disguising the defense’s fourth (and fifth or sixth) pass rusher and the coverage behind. In fact, there are a lot of under front concepts in the Phillips 3-4.

In contrast to the true 2-gap 3-4, there’s no clear “bubble” in a 1-gap front. The strongside end slides down in the guard-tackle gap and the nose tackle slants to the weakside center-guard gap. The weakside end may or may not be head-up on the tackle, sometimes aligning in a 5-technique. Moving the defensive lineman just a few inches changes the philosophy entirely. The diagram above shows an under-shifted 3-4, but over-shifted 3-4 fronts are also common.

By comparing the two 3-4 diagrams, it’s easy to see how the mind-set of the defensive linemen differs between the two flavors of 3-4. It’s clear that the two inside linebackers can be, if the linemen are disruptive at all, better protected from the blocks of interior linemen. You can see the lines of attack for a delayed ILB blitz or how each OLB might get a jump by shifting one defensive end to the outside of an offensive tackle.

The under-shifted 3-4 front, with or without a 2-gap end, is just one of many potential variations a coordinator may align for his front seven. In fact, a coach influenced by both flavors of the 3-4 might be tempted to meld both concepts with traditional 4-3 ideas and create a monster playbook with more than 50 fronts. And pull it off with amazing success.