Factbox: Key facts about tennis at the Tokyo 2020 Games

(Reuters) - The 2020 Tokyo Olympics involves 33 sports, including basketball.

Here are some key facts about basketball at the Olympics.

Introduced: Men's basketball has been a part of the program since 1936, while a women's competition was added in 1976.

This year a three-a-side - otherwise known as 3x3 - tournament is being introduced for the first time.

Events: Men and women each compete in their own standard format Olympic basketball tournaments, as well as the 3x3.

Each tournament features a group or pool stage, played in a round-robin format, followed by a knockout phase.

Skills and technique: Played the world over, basketball's unique moves and fast pace make it among the most popular sports. The 1992 Games were the first to allow NBA players to compete, adding celebrity firepower to the mix.

The new three-a-side competition, which uses one hoop instead of two, was added to appeal to the next generation of younger fans.

Top competitors: The United States sits squarely atop the leaderboard, with American women claiming gold in eight of their last nine Games and the men winning seven of the last nine.

Sources: International Olympic Committee, Tokyo Organising Committee of the Olympic and Paralympic Games, FIBA, Reuters

Graphic: https://graphics.reuters.com/OLYMPICS-2020-BASKETBALL/0100B5JG3YM/BASKETBALL.jpg

(Reporting by Amy Tennery; Editing by Toby Davis)