Editor's note: As architect of Texas A&M's Wrecking Crew defense (1989-93), Notre Dame defensive coordinator (1994-96) and head coach of the Irish (1997-2001), Bob Davie has been recognized as a top X's and O's coach. This season, Coach Davie will analyze offensive and defensive schemes as part of his season-long course on football for ESPN.com. Each week, he will break out the chalkboard and break down the X's and O's in college football.

One of the most common phrases heard when analyzing college football is the term "in the box." What we will do in this week's Football 101 is describe to you in simple terms what exactly coaches and analysts mean when they use that terminology. We will also explain the numbers matchups and how offensive and defensive teams are constantly trying to gain a numbers advantage over an opponent.

We will also use specific examples from the Nebraska-Miami 2002 Rose Bowl national championship game to show you how schemes can be exploited. Miami is a 2-back football team that has great balance between run and pass. Nebraska is a traditional 8-man front team. Their matchup in the 2002 Rose Bowl provides an excellent example of how two teams scheme against each other to try to gain an advantage in the box.

The box
What coaches mean by the term "in the box" is how many defenders are employed in an area close enough to the line of scrimmage where they can directly impact a rushing attempt by the offense. In the example shown below, the defensive team is using a traditional 7-man front to stop the run. You also see a base 2-deep coverage where four secondary members are deployed to defend the pass. In this instance it's obvious to see that the defense has chosen to use seven players close to the line of scrimmage to stop the run while utilizing the four defensive backs to play, primarily, pass coverage.

Defensive gap responsibilities in a 7-man defensive front
When deploying seven players to defend the run, each defensive player is assigned a gap. Each players' specific gap responsibility is lettered -- examples A, B, C and D. When we refer to a gap, we are referring to an area that the defensive player is responsible for if the ball threatens that spot.

7 blockers on 7 defenders
When using a 7-man front, it would appear that you have enough defenders to successfully stop the run. The seven defenders seemingly matchup with the offense's seven blockers. The problem is that the ball carrier is the eighth man, and he has the ability to choose whatever gap he wants to run in. The problem the defense has is that the linebacker to the tight end side in the drawing below must stay outside the fullback to play his B gap. The linebacker to the split end side must hold in the backside A gap because there is a possibility the running back may cut back in his gap. In essence, the defense is at a disadvantage because the ball carrier can run off the center's block in the A gap between the nose tackle and the tight end side linebacker. It is almost impossible to stop a great tailback when each of your defenders has a blocker on him. It's difficult for a defender to shed a blocker and make a play. Bottom line: offense wins this matchup.

Adding the 8th man to the box
To defend an excellent running football team, the defense must take one of their four secondary players out of deep pass coverage and drop him down "into the box." In the example below, the free safety becomes the eighth man in the box to the split end side. By having the extra man, this allows the split end side linebacker to come across the nose tackle and help the tight end side linebacker on the other side of the nose tackle. The free safety provides the replacement for the split end side linebacker and plays his old B gap responsibility. Because you have added the eighth man, you outnumber the offense eight to seven and the defense wins this matchup.

Weakness in the 8-man front
Obviously, if the defense decides to utilize the safety in the box to defend the run, they are left with only three deep secondary players to play the deep pass. You can choose to play a man-free coverage or a 3-deep zone. Either way your corners are basically assigned one-on-one coverage with the wide receivers. Nebraska's base plan and the one they utilized in the 2002 Rose Bowl was a man-free coverage with corners playing bump-and-run man-to-man coverage on the wide receivers and the outside linebacker being assigned man-to-man on the tight end. They had a strong safety deep to provide help if any one of the underneath coverage people couldn't matchup. Miami's plan was simple. On running downs they forced Nebraska to be in their 8-man front suspecting run. Then, they took advantage of their personnel and used play action off a run fake. The example below was the second offensive play of the Rose Bowl. It resulted in a 22-yard gain to Miami's tight end. Jeremy Shockey beat the outside linebacker off the line of scrimmage and the strong safety was no factor in the route.

Utilizing your receivers to defeat an 8-man front
Another way to attack the 8-man front besides using your tight end matchup with the outside linebacker is to take advantage of your wide receivers. They are in individual matchups with the cornerbacks. On running downs, this is a great opportunity for the offense to take advantage of one-on-one coverage and try to complete a deep pass. The example below from the 2002 Rose Bowl resulted in a 49-yard touchdown for Miami early in the game. Miami used play action, showing Nebraska the run to the tight end side. They then threw back to the split end and took advantage of Nebraska's cornerback slipping and falling. Result: touchdown.

Winning the numbers matchup in a one-back set
The same numbers game is played between the offense and defense with team's that use only one back in the backfield. Defensive teams are still faced with a decision: Do we overplay to the run or do we overplay the pass? In the example below, the defense decides to be stronger against the pass and uses their 7-man front and 2-deep secondary. As you can see, to play the 2-deep secondary the weakside linebacker must abandon his B gap and displace to cover down on the wide receiver to his side. The result of this will leave only six players in the box to defend the run. In the case of the defense leaving six men in the box, the offense has six blockers on the six defenders, and the A gap is voided.

7-man protection
In the diagram below, we show how Nebraska chose to defend Miami early in the 2002 Rose Bowl. The wanted to deploy seven defenders in the box against Miami's one-back set outnumbering their blockers seven to six. In order to do that, they had to bring their free safety out of 2-deep coverage and put him man-to-man on the wide receiver -- once again playing a man-free coverage. Miami exploited this matchup basically the same way they exploited Nebraska playing eight men against their two-back set. They went to the one-on-one matchup between the Nebraska corner and their wide receiver. Miami decided to use 7-man protection keeping all of their blockers in to matchup with Nebraska's seven potential rushers. They threw the ball deep to the wide receiver. Result: 46-yard pass play.

Summation
With everything you do in football strategy, there is a tradeoff. If you choose to outnumber an offense to stop their run, you obviously are weaker against the pass. Football is a complex game. The defense works extremely hard a disguising their intentions -- only revealing them right before the ball is snapped. Nebraska and Miami both had sound plans in the 2002 Rose Bowl. Nebraska had a very difficult matchup -- just like everyone else in the country did against Miami. Not only could the Hurricanes run the ball effectively, but they also had skill position players and could throw the ball as well. Both teams had sound plans and strategy. As in most cases, the team with the best talent won. In the 2002 Rose Bowl, that was Miami.

Term of the week: man-free coverage
Man-free coverage means the defense is playing man-to-man on the offensive team's receivers, but one of the safeties is free to play deep center field.