The 46 defense is an American football defensive formation. The formation comprises four down linemen, three linebackers, and four defensive backs. The 46 defense was originally developed and popularized by Chicago Bears defensive coordinator Buddy Ryan, who later became head coach of the Philadelphia Eagles and Arizona Cardinals. Today the scheme is currently used on a regular basis by the New York Jets head coach and defensive coordinator Rex Ryan, son of Buddy Ryan.
Unlike most defensive formations that take their names from the number of defensive linemen and linebackers on the field (i.e. the 4-3 defense has 4 linemen and 3 linebackers), the name "46" originally came from the jersey number of Doug Plank, who was a starting safety for the Bears when Ryan developed the defense, and typically played in that formation as a surrogate linebacker.
To stop a passing game, you can't stop it unless you put pressure on it. Now some people are good enough to put it on with a three-man rush; well, we're not. In fact, I don't know whether we're good enough to put it on with a four-man rush. If we have to send eight, we'll send eight, but we're not going to let you sit back there and pick us apart all day.
I had to use every bit of knowledge and experience and wisdom I had to come up with game plans to attack this defense. It's really the most singular innovation in defensive football in the last twenty years.
The 46 defense was an innovative defense with a unique defensive front, designed to confuse and put pressure on the opposing offense, especially their quarterback. A hyper-aggressive variant of the 4-3 base set, the 46 dramatically shifted the defensive line to the weak side (the opposite end from the offense's tight end), with both guards and the center "covered" by the left defensive end and both defensive tackles. This front forced offenses to immediately account for the defenders lined up directly in front of them, making it considerably harder to execute blocking assignments such as pulling, trapping and pass protection in general. Moreover, the weak side defensive end would be aligned one to two yards outside the left offensive tackle, leaving opposing tackle 'on an island' when trying to block the pass rush.
Another key feature of the 46 is that both outside linebackers tend to play on the strong side of the formation. To avoid confusion, the strong and weak side linebackers (who are no longer lined up on opposite sides) are often renamed the 'Jack' and 'Charley' linebackers, respectively. The linebackers line up behind the linemen somewhere between one and three yards from the line of scrimmage. The primary tactic is to rush between five and eight players on each play, either to get to the quarterback quickly or disrupt running plays, although dropping some players back into pass coverage after seemingly indicating that they will blitz (see zone blitzing) is another method of creating confusion. Ryan would use all of these rushers to out-man and overwhelm the offense. Another major key to the 46 is the ability of the cornerbacks to play man free and bump and run coverage. Bump and run can allow the defense to take away the quarterback's immediate decision-making ability, by disrupting the timing of short routes needed to make a quick throw to beat the 46 defense.
The formation was very effective in the 1980s NFL because it often negated a team's running game and forced them to throw the ball. This was difficult for many teams at the time because most offensive passing games centered around the play-action pass, a situation that often favored the defense even further with the quarterback lined up to receive the snap from directly behind the center.
Currently, the 46 is rarely used in professional and college football (with the exception of teams led by Buddy's sons, the New York Jets coached by Rex Ryan, and the 2010 Cleveland Browns when Rob Ryan was the defensive coordinator). This is largely because of the popularity of the West Coast Offense, used successfully by San Francisco 49ers head coach Bill Walsh, and other offensive schemes that rely on short, timed passes from formations with multiple receivers.
A minor weakness of the 46 defense can be too many defensive players lining up near the line of scrimmage to blitz, leaving areas open for receivers to catch passes. Also, short, timed passes can be thrown before the players blitzing have a chance to reach the quarterback. Another problem is that most teams do not have enough impact players to run the 46 as effectively as the 1980s Bears, the late 1980s Eagles and the 1993 Oilers did. Those teams fielded some of the best front-seven defenses ever, and included such players as Mike Singletary, Steve McMichael, Richard Dent, Dan Hampton, Clyde Simmons, and Wilber Marshall.
The ideas of the 46 defense are more often used in today's game by bringing a fourth defensive back (usually the strong safety) up closer to the line of scrimmage, as an eighth man in "the box" to help stop the run. Defenses today may also run safety blitzes and corner blitzes at crucial moments without committing wholly to the "46" defense. Up front, teams still use the concept of the "T-N-T" front, where defensive linemen are lined up over the center and the two guards. This makes it difficult for the interior linemen to reach any of the linebackers on the second level.
Lining up 
|This section does not cite any references or sources. (October 2009)|
This is where defensive players would line up against a normal Pro Set offense.
- Defensive ends: The weak side defensive end lines up one to two yards outside the weak offensive tackle. The strong side defensive end lines up directly in front of the strong side guard. The object of the weak side defensive end against the run is to protect against reversals and counters. Otherwise on pass plays he goes after the quarterback. The strong side defensive end is to make sure the offensive guard in front of him does not push him inside and does not get released to block the linebacker.
- Defensive tackles: The weak side defensive tackle lines up in front of the guard. The other defensive tackle essentially becomes a nose guard and lines up in front of the center. The main objective for the weak side tackle is the same as the strong side defensive end - to avoid being pinched inside or let the guard release to block the linebacker.
- Linebackers: The jack linebacker lines up on the outside shoulder of the strong tight end and, like a defensive lineman, lines up on the line of scrimmage. He ensures nothing gets outside of him on the run. He can do multiple coverages on the pass or he can blitz. The charley linebacker will line up on the line of scrimmage and on the inside shoulder of the tight end, to cover the tight end or making it difficult for the tight end to release easily. The middle linebacker will line up about four to four and a half yards off the line of scrimmage and directly in front of the strong offensive tackle.
- Safeties: The strong safety will line up four to four and a half yards off the line of scrimmage and will stand directly in front of the weak side tackle. The free safety will stand about ten to twelve yards away from the line of scrimmage and will stand directly in front of the weak side guard.
- Cornerbacks: Corners will line up seven to eight yards off the line of scrimmage in front of their receivers in man-free coverage or they will play up on the line of scrimmage in bump and run coverage.
When three or more receivers are used by the offense, the defense makes what is called a jayhawk adjustment. The charlie linebacker will step back to where the middle linebacker was in the normal alignment, the middle linebacker will move to where the strong safety was aligned and the strong safety will move out to cover the third receiver. If the offense uses a fourth receiver, the middle linebacker lines up in front of the center and the charlie linebacker would cover the fourth receiver.
See also 
- Mackall, Dave. Q&A with Doug Plank (October 19, 2006), The Pittsburgh Tribune-Review. Retrieved on February 16, 2008.
- Mayer, Larry (2009-01-26). "Maynard proud of record for most punts in Super Bowl". chicagobears.com. Retrieved 2009-01-27.
- Coaching Football's 46 Defense (The Art & Science of Coaching Series) (Paperback) by Rex Ryan
- Schweitzer, Preston & Tornabene-Zalas, Art. "46 Defense - Correcting the Flaws" (May 6, 2000), The Zone. Retrieved on August 22, 2007.
- Stoltz, Jeremy. "Chalk Talk, The 46 Defense" (May 24, 2007). Retrieved on February 16, 2008.
- Tom Worgo. "A blast from the past: remember Chicago's 46 defense? It's back again—this time in Baltimore, where Ray Lewis is trying to make it hum" (November 2005), Football Digest, Retrieved on August 22, 2007.
- ESPN.com. "The List: Best NFL defense of all-time", ESPN Page2, Retrieved on August 22, 2007.
- ESPN.com. "Greatest NFL teams of all time", ESPN Page2, Retrieved on August 22, 2007.
- Miller, John. "Chicago Bears: Bear's 46 defense" (September 2, 2004), AllExperts.com, Retrieved on August 22, 2007.
- ESPN SportsCentury, "Bears' 46 Defense" (2004) [TV]. ESPN. Released on January 29, 2004.
- Zimmerman, Paul. "A Brilliant Case for the Defense" (February 3, 1986), Sports Illustrated. Retrieved on February 16, 2008.
- Information on utilizing the 46 Defense
- Dusting off a classic
- Chalk Tallk: 46 Defense
- 1985 Chicago Bears Defense Playbook
- 1990 46 Buddy Ryan Defense Playbook