---
title: "Curl Concept Explained: Curl and Diagonal"
description: "The curl concept pairs a 12-yard curl with a diagonal to the flat (often called curl-flat) to stretch the flat defender. Why it beats Cover 3 and how to read it."
url: https://www.crucibletech.com/playbook/concepts/curl/
---

passing concept

# Curl Concept

The curl concept pairs a 12-yard curl with a diagonal to the flat, a combination many playbooks call curl-flat. It is one of the oldest low-high reads in football: the defender on that side cannot cover both.

![Curl passing concept diagram](https://www.crucibletech.com/playbook/img/football_11v11/concepts/curl.webp)

## How the Curl Concept Is Built

In Crucible's Curl, the outside receiver curls at 12 yards and a second receiver runs a diagonal to the flat at about 3 yards.

## What It Beats

- Cover 3, attacking the Curl/Flat defender.
- Soft zones that drop their underneath defenders too deep or too wide.

## How the QB Reads It

It depends on the play. In Crucible's Curl, Curl Hook, Curl Juke and Hank Curl you read the two inside linebackers and work inside out: a linebacker who widens toward a curl takes that side away, so work the other side; one who squeezes inside opens the curl on that side; both widening opens the throw over the middle. In Curl Snag against one high, you work the diagonal, then the curl, then the back.

## The Routes in Curl

-

![Diagonal diagram](https://www.crucibletech.com/playbook/img/football_11v11/routes/diagonal.thumb.webp)

Diagonal

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![Curl diagram](https://www.crucibletech.com/playbook/img/football_11v11/routes/curl.thumb.webp)

Curl

## Rep Curl Against These Coverages

-

![Cover 1 diagram](https://www.crucibletech.com/playbook/img/football_11v11/coverages/cover-1.thumb.webp)

Cover 1 31 plays to rep against
-

![Cover 3 diagram](https://www.crucibletech.com/playbook/img/football_11v11/coverages/cover-3.thumb.webp)

Cover 3 31 plays to rep against
-

![Cover 2 Tampa diagram](https://www.crucibletech.com/playbook/img/football_11v11/coverages/cover-2-tampa.thumb.webp)

Cover 2 Tampa 31 plays to rep against
-

![Cover 4 diagram](https://www.crucibletech.com/playbook/img/football_11v11/coverages/cover-4.thumb.webp)

Cover 4 31 plays to rep against
-

![Cover 6 diagram](https://www.crucibletech.com/playbook/img/football_11v11/coverages/cover-6.thumb.webp)

Cover 6 31 plays to rep against
-

![Cover 3 Buzz diagram](https://www.crucibletech.com/playbook/img/football_11v11/coverages/cover-3-buzz.thumb.webp)

Cover 3 Buzz 31 plays to rep against
-

![Cover 3 Weak Buzz diagram](https://www.crucibletech.com/playbook/img/football_11v11/coverages/cover-3-weak-buzz.thumb.webp)

Cover 3 Weak Buzz 31 plays to rep against
-

![Cover 5 diagram](https://www.crucibletech.com/playbook/img/football_11v11/coverages/cover-5.thumb.webp)

Cover 5 31 plays to rep against

+ 4 more in Crucible

## Curl Plays in Crucible

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![Curl diagram](https://www.crucibletech.com/playbook/img/football_11v11/plays/curl.thumb.webp)

Curl

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![Curl Hook diagram](https://www.crucibletech.com/playbook/img/football_11v11/plays/curl-hook.thumb.webp)

Curl Hook

-

![Curl Juke diagram](https://www.crucibletech.com/playbook/img/football_11v11/plays/curl-juke.thumb.webp)

Curl Juke

-

![Curl Snag diagram](https://www.crucibletech.com/playbook/img/football_11v11/plays/curl-snag.thumb.webp)

Curl Snag

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![Hank Curl diagram](https://www.crucibletech.com/playbook/img/football_11v11/plays/hank-curl.thumb.webp)

Hank Curl

## Related routes

-

Curl

## Related coverages

-

Cover 3 31 plays to rep against

Rep Curl in Crucible
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