Since naming Tom Thibodeau their head coach in summer 2010, the Chicago Bulls have sported a top-five defensive efficiency rating in each season.
They had the league's 10th-best defensive efficiency rating the year before Thibodeau came to town, per NBA.com, and in his first year the defense improved enough to be the best in the league.
The Bulls also had the league's best defense in the lockout-shortened 2011-12 season. It was due to the departures of defensive stalwarts Omer Asik and Ronnie Brewer as free agents, along with the extended absences of Joakim Noah, Luol Deng and Taj Gibson due to injury, that they vacated the top spot this season.
The personnel on hand in Chicago, along with Thibodeau's hard and fast principles, have combined to make the Bulls one of the league's toughest units to score on. However, as they proved in Game 1 of their Eastern Conference semifinals series against the Miami Heat, sometimes they can shut teams down completely, even without one of their best defenders.
Long story short, the Bulls feature some of the best individual defensive players in the league.
Joakim Noah may just be the NBA's best big-man defender. He's certainly on the short list along with 2013 Defensive Player of the Year Marc Gasol, Roy Hibbert, Tyson Chandler, Larry Sanders(!) and a few others.
Had he not missed 16 games (roughly 20 percent), Noah may well have made the top three of the DPOY voting this season. His pick-and-roll defense, especially when defending guards and wings on switches, is just masterful.
In Luol Deng and the emerging Jimmy Butler, the Bulls have two of the league's premier wing stoppers.
Deng was finally recognized for his defense with a second-team All-Defense selection last season, and he should garner either first- or second-team consideration again this year. His ultra-long arms and surprisingly strong frame allow him to guard three positions, and he most often takes the toughest defensive assignment on a night-to-night basis.
Butler, meanwhile, has emerged as one of the strongest, most versatile shooting guard/small forward defenders in all of basketball. On the ball or off, Butler is always in the right place at the right time, and his quick feet, strong base and long arms allow him to shut down any and all challengers.
He did a particularly excellent job bottling up Joe Johnson in the first round of the playoffs, and that carried over into the Eastern Conference semifinals as he made things difficult for LeBron James and Dwyane Wade all night in Game 1.
Taj Gibson—Chicago's backup power forward—is easily one of the best defensive players in the league to come off the bench. If he played more minutes, he'd be in yearly contention for All-Defense honors himself.
When the Bulls play him and Noah together, they're nearly impossible to score on. In the 620 minutes they shared the court during this 2012-13 regular season, the Bulls allowed only 91.8 points per 100 possessions, according to NBA.com—a figure that would have led the league by nearly five points.
That number was even lower when Gibson and Noah played with Butler and Deng. That fearsome foursome allowed just 90.6 points per 100 possessions, which would rate as the best defensive season in NBA history had a team sustained it for an entire year.
Even Chicago's weaker individual defenders—*cough* Carlos Boozer *cough*—are strong positionally. Guys like Nate Robinson and Marco Belinelli—who as recently as mid-March were causing disastrous breakdowns all over the court—have improved leaps and bounds over the last few weeks. They have been passable-to-decent defenders on most nights in the playoffs, even occasionally rising to "above average."
Any serious discussion of the Bulls defense has to start with the way it defends the pick-and-roll. On high screens, this is a three-pronged process that begins with the man guarding the ball-handler. His responsibility is to jump out on the high side of the pick and force the man with the ball to his off hand.
By not letting the ball-handler use the screen, the defense can cut off access to the middle of the floor, thus limiting the number of options the offense can pursue.
Working in conjunction with the ball-handler's man, the big defending the screener generally hangs back near the free-throw line, creating a pocket of space for the ball-handler to dribble into.
This positioning allows the big to both corral the ball-handler's drive and cut off the passing lane to the rolling screener at the same time. By enticing the dribbler into that pocket of space near the elbow, the Bulls hope he will A) take a pull-up jumper, B) dribble out and re-set the play or C) pick up his dribble.
The Bulls are perfectly fine with the first scenario, as a mid-range jumper is far preferable to a more efficient shot like a layup, dunk or three-pointer. The second option allows them to re-set their defense and engage in the whole process all over again.
The third scenario is the platonic ideal. It allows the player guarding the ball-handler to scurry back to his man, while also giving the big time to jet back to the screener. Precious seconds tick off the shot clock, making it far more likely the Bulls can force the offense into an inefficient look.
The last prong in Chicago's pick-and-roll defense strategy involves the three defenders whose marks are not directly involved in the pick-and-roll play. While many teams will have one or more of these defenders crash down into the paint to "tag" or "chuck" the roll man, the Bulls would prefer if they stayed home and denied kick-out passes to spot-up shooters.
Because of their athleticism, the Bulls are comfortable having their bigs—Noah and Gibson in particular—corral the ball-handler near the free-throw line, then sprint back to their own man in time to deny the pass. When combined with the other three players on the court staying home on their man, this strategy effectively chokes off every option for the offense.
Little slips occur occasionally, like Nate Robinson straying a bit too far from Norris Cole in the corner in the screen shot above, but the Bulls are often quick enough with their contests to cover up that type of mistake. This style of pick-and-roll defense helped them rank first in the league in points per play (PPP) allowed on spot-up attempts this season, per mySynergySports.
Against side pick-and-rolls, the Bulls, like many teams these days, like to "ice" or "down" the play. It's not uncommon to hear Noah, Boozer or Gibson scream "Ice! Ice! Ice!" when a side pick-and-roll is coming, as it lets the man guarding the ball-handler know which way they will be directing the man with the ball—toward the baseline.
The idea here again is to cut off access to the middle of the court, limiting the number of options the offense has. When it works well, the ball-handler dribbles into a pocket of space along the baseline and can easily be trapped. When it doesn't work, well...
The final piece of the puzzle is the strong-side overload defense against isolations. Thibodeau helped the Boston Celtics employ this strategy when he was an assistant coach for Doc Rivers, and it has spread throughout the league in the years since (though some may argue it had already started to trickle in even before that).
Note the positioning of Gibson and Noah in the two screen shots above. Even with Battier floating to the weak-side corner in the first shot and already stationed in that weak corner in the second shot, Gibson and Noah are zoned up on the strong side to cut off LeBron's path to the paint.
This positioning is designed to discourage forays to the rim and force individual dynamos like LeBron and Wade to take jumpers or throw skip passes over the top of the defense, which will allow enough time to recover to the shooter in the weak-side corner.
If they decide to attack the overload anyway, they often wind up with awkward-looking attempts in the lane like this. With Noah planted underneath the basket, LeBron just doesn't have the space to get off a clean look.
One way to beat the overload is to find that open man in the weak-side corner, but that only works if you actually make the open looks. Chicago doesn't surrender many of them, so not capitalizing on the ones that do present themselves is a deadly proposition.
The Bulls lack a high-powered offense so they're not some unbeatable juggernaut, but the top-notch defense gives them a shot to win every game.