There are certain things Ray Allen can control and there are others that are beyond him. Take the act of making a jump shot, for example. Few people have ever done this better than Allen and there are several details that have to be aligned -- form, positioning and so forth – and that’s before you account for a defender, or two, closing on him in a matter of seconds.
Everything has to be just so, which is why a self-described compulsive like Allen is more into process than results. “When you’re playing the game you don’t think it, you just let it happen,” he said. “It’s all rhythm.”
In order for his process to work, Allen likes to simplify things as much as possible. His job is to shoot the basketball and in order for him to do that he must have space. The easiest way to get space is to move. So, he runs.
“If I run hard enough, nine times out of 10 I get open,” Allen said. “So that’s why I try to run so hard.”
Allen isn’t a sprinter like Rajon Rondo or Nate Robinson. He’s a distance runner and distance running is a matter of consistent, controlled effort. In the condensed world of a 24-second shot clock every moment is precious. Running hard isn’t enough. There must be a purpose as well.
Allen’s movement is the catalyst that makes Celtics’ halfcourt offense function. Rather than rely on one-on-one plays and isolations, the Celtics try to make defenses decide who they’re going to guard and then they react once a decision is made. By constantly running around picks, Allen forces that decision.
Last week against the Spurs, he put on one of the great shooting displays the NBA has seen this season, and maybe one of the best performances of his career. He made 13 of 16 shots, with most of them coming off the same play. The Celtics call it ‘floppy,’ which is essentially a basic down-screen that allows Allen to pop off for jump shots.
There are two things that made this shooting exhibition so remarkable. First, the motion of the play takes Allen away from the basket, which means he has to turn, square himself and get his shot off in a precision-filled moment.
Second, the very nature of the shot – which comes outside the paint and inside the 3-point arc – is one of the worst shots in basketball. The area between 16-23 feet away from the basket is the dreaded no-man’s land in the NBA because it’s the furthest you can get from the hoop and still have the shot count for just two points.
Scroll down the list of the worst offensive teams in the league and you will see the same thing over and over again: too many shots from 16-23 feet.
Allen took shots 10 from that distance against the Spurs and made nine of them. That’s worth repeating: Ray Allen was 9-for-10 from the worst spot on the floor to shoot the ball, unless, of course, you’re Ray Allen.
Allen comes off those screens constantly and he has broken the play down to a science. For example, he discovered some years ago that he is right-eye dominant. A small thing perhaps, but once he came to that conclusion he also realized that when he comes off the screen on the right side he didn’t have to turn his body completely around because he can still see the target out of the corner of his eye.
“Coming the other way I have to turn more,” he said. “When I’m coming [on the left] side I have to turn so I have to be a little faster on [that] side and this side I don’t have to be as fast.”
That extra half-second comes in handy because there is a whole mental checklist he runs through whenever this play is called. Did his man go under, or over the screen? Did they switch off the big man setting the screen, which means a mismatch under the basket?
“Once I come from underneath the basket you kind of glance over your shoulder and see if your guy is trailing you or of he tried to shoot the pick, going over the top,” Allen said. “If both guys came with me, then I have a pass. It’s a split-second decision that you have to make.”
Allen doesn’t always consider himself a shooter in these situations. Rather, he sees himself as a playmaker. Sometimes the play is there for him, other times it’s for someone else.
“It’s also time and score,” he said. “Early in the game you want to try to build some kind of offensive rhythm. Sometimes I might have to develop some rhythm with my shot, other times it’s a team thing where we have to develop some kind of rhythm. Any time I come off the screen doesn’t mean that I have to shoot the ball.”  
Consider his interaction with Paul Pierce. It’s rare in the NBA when two wing scorers can play off each other so peacefully. Allen sometimes likes to set screens on the player guarding Pierce knowing that his man will be reluctant to leave him, but more often than not he’s content to get out of his way. 
“With Paul, so many people are going to swarm him and be around him, so I have to make sure that I give him space,” Allen said. “At the same time I almost have to dangle my man around him to make my guy make a decision: Am I going to help or not am I not going to help? I tell Paul all the time I’m just going to stay spaced and you’re going to have my side to operate on. You won’t have to worry about help.” 
Once they find out how teams will try to guard them, then they can make the proper adjustment. The Spurs, for example, were determined to make it difficult for Pierce to get his offense, which in turn freed Allen. The corollary is also true and one of the keys to the Celtics offense is looking for one another and making the extra pass.  
When it works, the Celtics halfcourt offense is a finely-tuned instrument of precision. They are the only team in the league that shoots over 50 percent from the field.
The Celtics rely on their shooting more than any other team in the league because they are the worst offensive rebounding team in the league (or the most indifferent) and they are in the bottom third in both turnovers and getting to the free-throw line. One more statistical insight: Over 64 percent of their made baskets come from assists, which is the second-highest rate in the league.
All of this is to say that on offense the Celtics are almost completely reliant on their ability to shoot the basketball, and in order to do that they must be aware of each other and willing to make the extra pass.
They all have a role in this. Pierce commands the most attention. Kevin Garnett keeps the floor spaced with his outside shooting ability. Shaquille O’Neal makes it impossible for his man to help because he is standing right under the basket. Rajon Rondo makes the whole thing go with his decision-making. And Allen runs.
The end result after all the strategies, movement and passes have been accounted for is more often than not an open shot. “On this team you don’t really need to take a tough shot,” Allen said. “We’re all capable of making big plays but you don’t really need to take a tough shot.”
Funny thing about that Spurs game. In the final seconds Allen went to the line with a chance to ice the game. After an evening spent making the most difficult shot in basketball, the career 89 percent free throw shooter missed them both. This confused Allen, but it didn’t worry him. “When I think about the first free throw I don’t know how I missed it,” he said. “Those are the ones that are always perplexing to me.”
As much as he has mastered his art, there are still things beyond his control.