"Vertical" Nature, Origins
The Air Coryell offense owes a debt to Sid Gilman, but the it took it's own course (and it's name) under coach Don Coryell with the San Diego Chargers. Emphasizing the Tight End as a downfield receiver, Coryell's San Diego Chargers teams were the home of hall of famers QB Dan Fouts, WR Charlie Joiner, and TE Kellen Winslow. Recognizing the talent of this trio, Coryell was unafraid to air the ball out. Fouts threw for 4,802 yards in 1981(!).
The Air Coryell offense is often labeled a "vertical" offense because the coaches that run it tend to throw the ball deep and create big plays through the passing game. However, this "vertical" nature of a deep passing game is often conflated with the other vertical tenant of the Air Coryell offense. Unlike the (other) West Coast Offense, which tended to stem one receiver on a drag route or another non-vertical stem, the Coryell offense sent all three receiving threats up the field to begin passing plays:
Like the West Coast Offense, plays are called with a formation, number, and a few words or tags in the Coryell offense. Unlike the WCO, some of the numbers and words in the Coryell offense are directly related to the individual routes being run by the receivers. As an example let's take a look at the play "Split right, scat right, 545 F post."
In the Coryell system formations are called with a word that describes the formation along with the direction of strength such as "Split right" (for split backs with the TE on the right) or "I left" (for backs in the I formation with the TE to the left).
(click images to enlarge)
Protections are usually called with one word and a direction such as "scat right" for the protection used here.
The left side of the "scat right" protection involves the back. Because he is given no route tag, H will block the ROLB if he blitzes and then release into his default route (here a swing) if there is no blitz. Each team will have a default route for the 5th player (in this case H), who can be tagged to run a specific route if necessary.
The Center will block the man over him, while the Left Guard will take the RILB if he blitzes. The Left Tackle will block the RDE.
The Right Tackle will block the LDE, while the Right Guard has a dual read between the LILB and the LOLB. If the LILB blitzes, the guard will block him. If he does not, he will work out around the RT to block a blitzing LOLB. If neither blitz he will help other linemen, and if both blitz the QB has to throw hot. (Note: dual-reading by guards is almost non-existent in today's NFL, but this is an Ernie Zampese play from the Cowboys' offense in the 1990s. This sort of dual read is mostly done by backs in today's NFL.)
Passing plays are called with a 3 digit number followed by a route tag for one or both backs (or different personnel). The three numbers in the playcall refer to the routes of the left WR, the TE, and the right WR respectively.
So in "Split right scat right 545 F post" the left WR will run a 5 route, the TE will run a 4, and the right WR will also run a 5 ("545").
Route trees vary from team to team, but generally odd numbers break outside and even numbers break inside. Higher numbers break further down the field, with the 9 route being a "go" straight down the field. Inside receivers have a different route tree than outside receivers. Here is the outside receiver route tree Ernie Zampese (a Coryell disciple) used in Dallas:
And the inside receiver route tree:
The "F post" part of the play means that the F player will run a post route (the F post is a little different than a "normal" post) which will complete the concept.
A package of plays: make them look the same
Sending three receivers on vertical stems forces the defense to defend the width and depth of the field, but it has another benefit as well: multiple concepts off of these stems look the same. This means the offense can show its intentions late and it is harder for the defense to distribute their coverage because they have to defend multiple possibilities off of the vertical stems. I cannot understate the importance of an offense hiding it's intentions until it is too late for the defense.
Three additional concepts are typically run in a package with 545 F post. They are 839 F Flat, 435 F Cross, and 432 F Corner. To demonstrate how they work to keep the defense on it's heels I'll lay all four concepts over one another:
With multiple route combinations off of the same initial look the defense must play the offense honest, and when the defense has to play honest the offense wins. Up next I'll take a look at how the QB makes his reads in this series of plays.