Football coaches need a fast, shared language for where a run is going and where a defender should line up. That language is built on gaps (lettered spaces between offensive linemen, usually used by the defense) and holes (numbered spaces used by the offense to call run plays). Numbering varies by program, but the system below is the most common.
The gaps: A, B, C and D
Gaps are the spaces between offensive linemen, lettered from the center outward. They mirror on both sides of the ball.
| Gap | Location |
|---|---|
| A gap | Between the center and each guard |
| B gap | Between each guard and tackle |
| C gap | Between the tackle and tight end, or just outside the tackle if there is no tight end |
| D gap | Outside the tight end |
Defenses assign each player a gap to control. A linebacker “fitting the A gap” is responsible for any runner who tries to go between the center and guard.
The holes: offensive numbering
Most teams number holes with even numbers to the right and odd numbers to the left, getting bigger as you move outside:
- 0 and 1: between the center and guard (the A gaps)
- 2 and 3: between guard and tackle (the B gaps)
- 4 and 5: between tackle and tight end (the C gaps)
- 6 and 7: outside the tight end (the D gaps)
- 8 and 9: wide, around the end
Some programs flip it (odd right, even left) or number holes on each lineman instead of between them. Always learn your team’s playbook.
How play calls use hole numbers
Run plays often combine the ball carrier’s number with the hole number. Backs are numbered by position, commonly 1 for the quarterback, 2 for the fullback and 3 for the tailback. A call like “32” tells the tailback (3) to run through the 2 hole, between the right guard and tackle. “24” would send the fullback through the 4 hole.
Defensive technique numbers
Defensive linemen use a separate numbering system, popularized by coach Bum Phillips, to describe exactly where they line up:
| Technique | Alignment |
|---|---|
| 0 | Head-up on the center |
| 1 | Shaded on the center’s shoulder |
| 2 / 2i | Head-up on the guard / inside shoulder of the guard |
| 3 | Outside shoulder of the guard |
| 4 / 4i | Head-up on the tackle / inside shoulder of the tackle |
| 5 | Outside shoulder of the tackle |
| 6 / 7 | Head-up on the tight end / inside shoulder of the tight end |
| 9 | Outside shoulder of the tight end |
That is why you hear about a “3-technique” defensive tackle: a player lined up on the outside shoulder of the guard, in position to shoot the B gap.
Why it matters
- Offensive linemen know which defenders to block based on the hole being attacked.
- Ball carriers know their aiming point.
- Defenders know which gap they own, which prevents big runs.
Play calls decoded
Once you know the numbers, a play call reads like an address. The first digit usually names the ball carrier and the second names the hole.
| Call | Ball carrier | Hole | What it means |
|---|---|---|---|
| 32 Dive | 3 back (often the fullback) | 2 (right A gap area) | Quick inside run just right of centre |
| 24 Power | 2 back (often the halfback) | 4 (right B gap area) | Downhill run with a lead blocker |
| 47 Sweep | 4 back | 7 (left edge) | Outside run to the left |
| 28 Toss | 2 back | 8 (right edge) | Pitch to the back running wide right |
Teams use different numbering schemes, so a playbook defines its own backs and holes. The common rule is even numbers to the right and odd numbers to the left.
Gaps, holes and techniques together: an example
Picture a 4-3 defence against a right-handed offence. The defensive tackles line up in the A and B gaps with 1 and 3 techniques, the ends set up in 5 or 9 techniques outside the tackles and tight end, and the linebackers fill the remaining gaps behind them. The offence calls a run to the 4 hole, aiming at the right B gap. Every defender’s job is to keep the gap they own closed, which is why the gap names matter to both sides of the ball.
Common points of confusion
- Gaps are defensive language, holes are offensive. They describe the same spaces from different sides.
- Numbers vary by team. Some teams number holes through the linemen rather than the gaps between them.
- Tight ends change the count. Adding a tight end creates an extra gap on that side.
How to learn the system quickly
- Draw the offensive line on paper and label each gap with its letter on both sides of the center.
- Add hole numbers using your team’s convention, even on one side and odd on the other.
- Place defensive linemen at common techniques, such as 0, 1, 3 and 5, and note which gap each usually controls.
- Read a few play calls from your playbook out loud and point to the hole each one targets.
- Walk through the plays on the field so the numbers match what you see.
Gap responsibilities in common defensive fronts
Defensive coordinators assign every gap to a player so no running lane is left open. In a one-gap system, each defender attacks a single gap and trusts teammates to cover the others. In a two-gap system, a lineman engages the blocker head-up and is responsible for the gaps on both sides, reading the play before committing. Linebackers and safeties fill the remaining gaps depending on the call, and when a defender leaves their gap, big runs often follow.
Common mistakes when learning gaps and holes
- Assuming every team numbers holes the same way.
- Confusing a player’s technique number with the gap they are responsible for.
- Forgetting that gaps move when the offense uses an unbalanced line or adds a tight end.
- Memorising numbers without watching how blocks and defenders actually move on film.
Frequently asked questions
How are holes numbered in football?
In the most common system, even numbers are on the right side of the line and odd numbers on the left, starting at 0 or 1 next to the center and increasing toward the sideline. Some teams reverse this or use their own system, so always learn your playbook’s version.
What is a 3-technique?
A 3-technique is a defensive lineman aligned on the outside shoulder of an offensive guard, usually responsible for the B gap. It is a popular alignment for quick, disruptive defensive tackles because it creates one-on-one matchups with the guard.
What is the difference between gaps and holes?
They describe the same spaces between offensive linemen. Defenses usually use letters (the A, B, C and D gaps), while offenses usually use numbers (holes) in their play calls, so the A gap and the 0 or 1 hole refer to roughly the same area next to the center.
These are coaching conventions rather than official rules, so numbering can vary by team.
