Tuesday, January 31, 2012

Defense pt. 1 - A Defensive Primer

Defense pt. 1 - A Defensive Primer

Background Info

Up until now we've focused entirely on the offensive end but today I want to take a change of direction and look at the other end of the court. You have likely heard the phrase, "the best defense is a good offense", today we take the opposite stance and the reasoning behind that sentiment is probably pretty clear. First, solid defense relieves the pressure on your offense to score more points. Second, the more your defense makes the other side work for its points, the more tired and frustrated they will become. Lastly, solid defense can break up the other team's offensive options and plans.
How does the defense try to achieve these goals? Defense operates in both sets and types. A set, much like our discussion on offense, is a description of the formation created by the players on the court. A type is a description of the way the defense interacts to the movement by the offense. The defense will pair a set with a type of and we'll see how these pairs can affect how the defense operates on the court.
This first part is in no way intended to be comprehensive but instead is intended to introduce you to the basic defensive concepts. In the future, we will apply these concepts more thoroughly and recognize the differing defensive philosophies.
Let's start with the sets.


The first set we'll look at is the 2-3 set.
At this point the formation shouldn't come as a surprise to you based on the name. We see two defenders on the elbows and three defenders lower to guard the middle and corners. A notable advantage to this set is how much area is covered in the interior. You'll also notice the C is in the paint in the set, because of the defensive 3 second rule he will have to be careful to reset himself outside the paint otherwise he will constantly cause a violation.
Here we have a 3-2 set. This set is obviously similar to the 2-3 except this set front loads the defense, adding some perimeter support in exchange for paint and baseline protection.
This is the 1-2-2 set, in many ways it's similar to the 3-2 set except the wings are sunk to the elbow position.
Already you should notice a few things about these set choices. Each has its advantage and disadvantage and the choice of which set to use is dependent on the kind of offense you're facing and the abilities of your roster. For example, when we compare our 3-2 set and 1-2-2, the wings are sunk to the elbows. This gives the coach an interesting dilemma. If the coach feels that the biggest threat is perimeter shooting, he may opt for the 3-2 set over the 1-2-2 set since it puts the wing positions in a better position to contest shots. On the other hand, if the coach is more concerned about driving lanes to the basket, he may lean toward the 1-2-2 over the 3-2 set because driving lanes are more clogged and gives a better opportunity for defenders to help contest drives.
Also notable are the 2-1-2 and 1-3-1 set and at this point I  think you can envision what those look like. Important to note is that each set has its advantages and disadvantages, choosing between them is a matter of trying to maximize your advantages while exploiting the offense's disadvantages.
Let's look at how defensive types play a role in this.


Defensive philosophies are integrated into defensive sets and thus, similar to the triangle offense and motion offense, are not a description of formation but rather a description of movement. We'll talk about two different defensive philosophies, the first is man-to-man defense and the second is zone defense.
Traditional Man-to-Man
The most common philosophy is man-to-man. Man-to-man defense is where the defensive players simply try to stick to a single offensive player.
Here we see the flex motion offense introduced in our discussion about the Bulls except this time I added defensive players that are covering using man-to-man.
Let's step through this animation and see what happened. The offense starts in a 1-4 low set and the defense is playing man-to-man.
Notice how each defender tries to stick to his assigned man regardless of where they move on the court. Also notice how the offense attempts to free up players using screens. This is the common struggle in basketball and should come as no surprise to you - freeing up offensive players covered by their defensive players. The offense was able to free up the SF off a screen by the C, the PG was screened for by the PG but in my example the defensive PG was able to stick to his man, and the C was freed up by popping off his screen.
Let's see how this differs from zone defense.
Zone Defense
Zone defense focuses on covering areas of the court rather than players and is more closely associated with using defensive sets because of the focus on areas of the floor. Let's take a look at what I mean:
Here we have the 2-3 zone with each defender's area of responsibility colored. Notice there are some areas not covered by the zone. The top of the arc, the corners, the positions between the wing and corner, the baseline, and just below the free throw line (though not pictured very well here) are all not covered well by the zone. The offense's goal then is to try to manipulate this in their favor while the defense has to prevent the offense finding a way to penetrate the zone. Let's see how the zone moves.
Notice that when the ball moved, the defenders moved toward the ball while remaining in their area of responsibility. Generally, the goal of the zone is to prevent penetration into the lane and force perimeter shots. Let's watch a longer sequence to get a feel for how the movement works.
Did you notice the defenders moving toward the ball movement rather than covering individual players? When faced with a wall of defenders it can dissuade the ballhandler from trying to drive to the hoop and instead cause him to pass. The ballhandler is then forced to focus more on passing to the right option which can eat up time as nobody is looking to shoot. Also notice at the very end the C ended up trapped in the corner. Players are willing to break from the zone if it means forcing a trap but they should keep in mind that this is a gamble which could lead to an open shot on the weak side.
Let's watch the Mavericks play some zone defense.

Now let's look at a diagram of what we saw.
The Mavericks are playing a 2-3 zone defense in this clip. As I mentioned earlier, one of the weaknesses of the 2-3 zone is the baseline and here we see Wade recognize the 2-3 zone and attack the baseline. The Mavericks scramble to cover that area but Chandler is unable to get there in time. Also notice that Haslem is in another weak area of the zone right by the free throw line.

Modern Swarm Defense

Modern basketball most commonly uses a combination of man-to-man and zone. It is mostly man-to-man, and in fact is usually even simply called man-to-man, but in reality is actually a hybrid of the two systems.
Swarm defense begins as man-to-man but players will switch off their man to aid off screens and defensive players will rotate to provide better coverage.
Let's look at an example:

Let's look at an animation of what we saw.
Notice how we began with a man-to-man defense but the defense switched to put additional pressure on the key offensive threats.
The Mavericks have two main offensive threats, the first option is likely Dirk Nowitzki and the second option is Jason Terry.
The offense ran a double screen for Nowitzki and Stevenson. When Nowitzki caught the ball, Chalmers and Miller began to hedge toward Nowitzki. They did this to look for opportunities to trap or contest his shots. The defense is making a conscious gamble to be late to contest Barea's corner shot or late to contest Stevenson's wing shot in return for more pressure on Nowitzki. In this case, the trap on Nowitzki was successful and he has to pass out to Stevenson at the wing.
Stevenson has a couple options at this point. He can either try to shoot, drive to the basket, or pass. The defense is very aware of the options and must be sure not to overcommit when they respond or they risk leaving a player open for a shot. Lebron has been at the low post reading the offense and notices that Miller trapped Nowitzki, this means that he will be unable to rotate to Stevenson if the pass is made. When Nowitzki turns to look for a pass, Lebron knows exactly where to go, which is to help off of denying the low post and out to the wing. Stevenson then opts to pass to Terry in the corner.
Since Lebron picked up Miller's man, Miller now rotates to trap on the Mavericks' second option, Terry, to try to corner trap him. The trap forces Terry to shoot the ball with 5 seconds left on the shot clock over two defenders. Terry makes the shot but the defense has to be happy with how difficult they made it. The best a defense can do is make the offense difficult, it cannot account for players making those shots - thus, they have to consider this a good defensive trip.
Now that we looked at what happened, let's look at what didn't happen.
This is the same play but this time Miller doesn't rotate back to Terry. I wanted to show the difference to help demonstrate the difference between good defense and bad defense. Good defense will constantly rotate to cover all the options, bad defense results in open shots. Good defense relies heavily upon communicating when to rotate, all it takes is one missed rotation to give up an open shot.
So how would we classify swarm defense? Is it man-to-man or is it zone? Well, like I stated earlier it's a combination of both. There will be some trips where everyone stays on their man, there will be other trips where players are constantly switching off each other. It really depends on how the coaching staff has decided to handle their opponent. Some players might deserve more attention defensively than others or sometimes it's even certain areas of the floor that need special attention (e.g. defend the paint or guard against the 3pt shot). It's also largely based on the abilities of your roster, you can't ask a slow C to try to rotate out to the perimeter and thus you need to account for that in your defensive plan.

Guarding the Pick and Roll

The pick and roll is the most common play in basketball, mostly because it's quick and effective. There are a few things that teams do to try and reduce its effectiveness. Let's look at this clip to see one example:

Did you notice what Haslem did? When Nowitzki ran up to set the pick, Haslem went above the pick to force Barea to go over him. This made Barea take a longer path toward the basket allowing Chalmers to step between the gap created between Haslem and Nowitzki and making it easier for Chalmers to recover on Barea. Since Barea has a longer path to the basket, it also gives the help defense some additional time to get in place to defend a drive. Here Barea was still able to get by Chalmers but Bosh had enough time to get in position for the good contest.

Here we see Barea go over the pick to guard Chalmers on the pick and roll. Barea gets beat but Mahini is waiting for him. Mahini did not rotate back to his man once Barea recovered and that leaves Bosh open to receive the pass. Barea likely went under the pick here for two reasons. First, he's small and quick which makes it easier for him to negotiate picks and recover to his man. Second, Chalmers was 2 for 2 from 3pt range up to this point in the game (including one on the previous possession) so he wanted to be in possession to contest a possible 3pt shot.


This first part is intended to provide a primer to the way teams approach defense. Hopefully what you gained from this part is the balance that teams must strike on defense. Teams recognize the advantages and disadvantages to the defensive systems they run and try to apply the system that provides the most benefit with the least detriment.
Next time we'll take a deeper look into some of the defensive philosophies teams apply and how that alters their approaches. We'll also look at some clips and try to apply what we've learned so far to identify what choices the defense has and why they made the choices they did.

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