Since James Naismith’s fateful decision to hang a peach basket on the wall at a YMCA training school in western Massachusetts in 1891, basketball has been a quintessentially American sport.

For fans in the United States and worldwide, the sport is overwhelmingly viewed as a five-on-five game, whether it’s in the NBA, in college or in international competition.

At the Olympics, though, there’s a different format.

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Three-on-three basketball (commonly shortened to 3x3 basketball) is a relative newcomer to the Olympics, debuting at the 2020 Tokyo Games in 2021. It’s back at the 2024 Paris Olympics, with the United States competing on both the men’s and women’s side.

Though millions of American viewers tuning into the Olympics are intimately familiar with five-on-five basketball after years of consuming it, the 3x3 game is significantly different, from the rules to the pacing to the strategy.

Here’s what you need to know about 3x3 basketball, including rules, format and the Team USA rosters that will be vying for gold medals in France:

3x3 basketball court size, dimensions

Among the myriad differences between 3x3 and five-on-five basketball is the size of the playing surface.

While traditional, five-on-five basketball is played on a 94-foot-long court, 3x3 basketball uses a condensed court that’s 36.1 feet in length and 49.2 feet in width, with a single hoop at one end and an end line on the other.

Though the point values are different, the arc behind which players can earn an extra point with a made shot is the same — 22.1 feet from the center of the hoop.

Why is 3x3 basketball halfcourt?

With four fewer players on the floor at a given time (two for each team), the court doesn't need to be nearly as big as it is for five-on-five basketball.

For some watching the Paris Olympics, it's a comfortably familiar setup, as pick-up basketball — where 3x3 basketball can trace its roots — is often only halfcourt, with players bringing the ball back to the top of the key between possessions

2024 PARIS OLYMPICS: Meet the members of Team USA for the 2024 Olympics

Rules for 3x3 basketball

The basics of 3x3 and five-on-five basketball are largely similar, with the same rules governing fundamental elements of the sport like ball-handling, along with the same characteristics of the court – a lane, a free-throw line, a 10-foot rim and a semi-circular arc behind which players can try to make a shot worth an additional point.

Beyond that, the two sports differ in easily noticeable and perhaps jarring ways.

As the name of the sport makes clear, there are only three players per team allowed on the court at a time in 3x3 basketball, with each team permitted only one substitute for a four-player roster that’s one-third the size of an Olympic five-on-five basketball team. The substitutions are less formalized, too, with players simply tagging in during a dead ball rather than going to the scorers’ table.

The ball is slightly smaller in 3x3 basketball, weighing 620 grams, the same as the balls used for FIBA-sanctioned five-on-five competition, but is 72.39 centimeters in diameter, compared to the 74.93 centimeters of a five-on-five ball.

The defensive team can win possession with a defensive rebound, steal or block. When a defensive player gets control of the ball inside the arc, they need to dribble it out or pass to a teammate beyond the arc before their team can attempt a shot.

Scoring in 3x3 basketball is different, too, with shots from inside the arc worth one point and shots from beyond it worth two. Free throws, like in five-on-five basketball, count for one point.

REQUIRED READING: Men's 3x3 basketball at 2024 Paris Olympics: How it works, Team USA stars, what to know

How long is a 3x3 basketball game?

Rather than the FIBA-regulated four 10-minute quarters, 3x3 basketball is much shorter.

The first team to 21 points wins the game. If neither team makes it to that threshold in the allotted 10 minutes of game time, the team with the most points is declared the victor. If the teams are tied in that instance, there’s an overtime period. The first team to score two points in overtime wins, with the team that started the game on defense getting the first possession of the extra period.

Like it five-on-five counterpart, 3x3 basketball has a shot clock, but it’s just 12 seconds, half the time of a regulation 24-second shot clock used in NBA and FIBA competition.

3x3 basketball Olympics winners

In its debut as an Olympic sport at the 2020 Tokyo Games, Latvia won the gold medal in the men’s competition while the United States won on the women’s side with a team featuring a quartet of WNBA players — Kelsey Plum, Jackie Young, Allisha Gray and Stefanie Dolson. Two of the players from that American team, Plum and Young, are now on Team USA for five-on-five basketball at the 2024 Paris Olympics.

REQUIRED READING: Women's 3x3 basketball at 2024 Paris Olympics: How it works, Team USA stars, what to know

Team USA 3x3 basketball rosters

The Americans will be making their debut in men’s 3x3 basketball at the 2024 Paris Olympics after failing to qualify three years ago while the women will look to successfully defend their gold medal, albeit with an entirely different team.

The women’s team features a pair of active WNBA players — Rhyne Howard of the Atlanta Dream and Dearica Hamby of the Los Angeles Sparks — while the men’s team is headlined by former national college player of the year and NBA lottery pick Jimmer Fredette.

Here are the Team USA rosters for 3x3 men’s and women’s basketball at the 2024 Paris Olympics, along with the heights of each player:

Men

• Jimmer Fredette, 6-foot-2

• Dylan Travis, 6-3

• Canyon Barry, 6-6

• Kareem Maddox, 6-8

Women

• Hailey Van Lith, 5-9

• Rhyne Howard, 6-2

• Cierra Burdick, 6-2

• Dearica Hamby, 6-3

This article originally appeared on USA TODAY: Why is 3x3 basketball halfcourt? Rules, court dimensions for 2024 Paris Olympics