It was banned for decades. Now the Miami Heat can use it to win a title.

One of the catchiest chants in the NBA is an acknowledgment of one of the game’s most thankless duties: “Defense!” Clap. Clap. “Defense!” It rained this week as the Miami Heat took on the near-impossible challenge of slowing down two of the league’s most fearsome players — Nikola Jokic and Denver Nuggets’ Jamal Murray — during the NBA Finals in front of their home crowd.

The loftiest defensive matchups in the NBA tend to be one-on-one clashes, where opposing players come face to face. But that’s hard work. Really difficult. Maybe you can hold off an explosive goalscorer like Jokic or Murray for a possession or two. But every time on the ground? 48 minutes long? With an undersized roster that has endured the long grind of the post-season?

Good luck. For more than 50 years, the NBA refused to let teams do it any other way. It was hand-to-hand defense or failure. But now teams can be more creative in how they try to pin their opponents. And no team is more creative than the Heat, playing more zone defense – a scheme where defenders guard sections of the field rather than individual players – than any other team in the league.

On Wednesday in Game 3, that meant two players had to trap Denver’s inbound pass, two more in midcourt and one protecting the basket on the other side — a 2-2-1 zone press — early in the second quarter .

By the time the Nuggets managed to get the ball on court, only 14 seconds remained on the shot clock and the Heat’s defense had turned into a half-court zone – a 2-3 set, with two players on top the edge and three along the baseline. Murray, the Nuggets’ point guard, missed a 3-point attempt from the left corner and the Heat ran for a tie.

Unfortunately for the Heat, that was about as good as it got for them in their 109-94 loss to the Nuggets, who took a 2-1 series lead ahead of Game 4 on Friday in Miami. Murray and Jokic both finished with triple-doubles for Denver, which, for one game at least, was largely unfazed by Miami’s shape-shifting defense.

,,We didn’t put up much resistance”, said Heat Coach Erik Spoelstra, who complained about his team’s lack of effort, but found it an anomaly. He added: “I think the thing we’ve proven over and over again is that we can win and find different ways to win.”

And one of those ways is with their zone defense. There’s a difference in talent in this series: the Nuggets have more of it thanks to their roster of expert shooters and the all-around wizardry of Jokic, a two-time winner of the NBA’s Most Valuable Player Award. So, in an effort to slow the pace of the game and make up for their lack of size, the Heat occasionally let their man-to-man defense slip by meddling in a particular zone.

This is nothing new to them. Miami played zone on 19.7 percent of its defensive possessions during the regular season, according to Synergy sports, a scouting and analysis service. The Portland Trail Blazers, who played in zone 14.9 percent of the time, were in second place, and the Toronto Raptors (8.4 percent) were third.

More importantly, the Heat—even during the regular season struggles that nearly kept them out of the playoffs—used their zone to great effect, limiting opponents to 0.937 points per possession. In comparison, opponents averaged 1,009 points per possession against their man-to-man defense.

Miami plays a little less zone defense in the playoffs — zone accounted for 15.7 percent of its defensive possessions prior to Game 4 — but no other team has used it as much. And the Heat has had some success with it, holding opponents to 0.916 points per possession versus 1.003 points per possession with man-to-man defense.

“I think it’s effective,” said Heat point guard Gabe Vincent, “because it’s different.”

Jim Boeheim, who recently retired as a men’s basketball coach at Syracuse University after 47 seasons, was so well known for his 2-3 zone defense that he became synonymous with it. But in his early years at Syracuse, he actually coached more hand-to-hand defense.

“We had a zone and we practiced it, but not all the time,” Boeheim said. “But then we’d be in trouble with someone, and you’d put the zone there, and they couldn’t score!”

Most teams didn’t practice it, and they rarely faced it in games.

“It could just screw someone up,” Boeheim said. “And if your opponent is only attacking one or two guys, you can cheat a little bit against those one or two guys, and that can cause problems.”

The zone remains somewhat of a novelty in the NBA, which essentially banned it for the first 50-plus years of the league’s existence. Before the advent of the shot clock in 1954, the concern was that too many teams would fill the area around the basket with defenders and slow play to a crawl at a time when the league was desperately trying to grow its crowd.

Later, critics viewed the zone as a gimmick for teams to camouflage poor individual defenders, especially as the league continued to glorify one-on-one matchups. The low zone was stigmatized. But over time, fouls stopped and scoring dwindled as games devolved into a seemingly non-stop series of isolation sets, with players on the weak side of the pitch luring defenders away from the ball.

Ahead of the 2001–02 season, the NBA had seen enough and eliminated its illegal defense rule, which meant teams could play zone — or use any other type of defense that suited them. The twist was that the change was to give space and pass on violations.

However, the zone remains quite unusual for several reasons. NBA rosters are packed with long-range shooters, and when passes bounce back and forth, zone defenders are often too slow to react, leaving opponents with an open mind from 3-point range. Defenders are also prohibited from camping on the court when not guarding an opponent – known as the defensive three-second rule.

“And that changes everything,” says Alex Popp, the head boys basketball coach of the IMG Academy postgraduate team in Bradenton, Fla. protect the paint.”

For the Heat, the zone has value. If it was initially born out of necessity – as a way for Spoelstra to take on bigger teams and hide some of its weaker defenders – it has turned into an asset. For long stretches of the Eastern Conference Finals against the Celtics, Boston appeared stunned by Miami’s traps, often settling for (errant) jump shots rather than attacking the rim.

Whenever the Nuggets bring the ball up, they have to do a mental calculation: What kind of defense are they going to see? The zone adds an element of unpredictability.

“I think it’s something that can work,” Boeheim said, “especially in short windows.”

Kyle Lowry, the Heat’s backup point guard, recently recalled a formative period from his youth when his coaches taught him about the zone press, falls, and the basic 2-3 formation. When asked about those experiences, he knew where the line of inquiry was headed.

“If you’re talking about our zone, that’s pretty cool,” Lowry said.

Okay, what makes it cool?

“Sometimes it works,” he said.

The zone of Miami is not static. It changes from game to game and even possession to possession, with dozens of permutations based on which opponents are on the floor – or even Spoelstra’s whims.

Bam Adebayo, the team’s starting center, said they are drilling the zone “to the point where we are fed up”.

Spoelstra would rather walk on hot coals than discuss his schedule picks during the NBA Finals, but his players have acknowledged the zone’s amorphous nature.

“Spo is doing a great job preparing us all year to be ready for situations like this, to be able to switch in timeouts, switch schedules, switch defenses,” said heat guard Max Strus before Game 3.

For Game 4, Miami will likely unveil a new schedule or slightly different look. It may not matter — “I think Denver is too good,” Boeheim said — but the Heat has struggled before. Their zone helped.