It is that time of year again. Millions of basketball fans across the United States are gearing up for several weeks of fast-paced competition to crown the next men’s collegiate basketball champions.

Hosted by the National Collegiate Athletic Association (NCAA), which administers university athletics in the US, the annual tournament — known as March Madness — officially begins later this week.

It is one of the most anticipated sporting events in the US, and more than 18 million people tuned in to watch last year’s final, which saw the Kansas Jayhawks defeat the North Carolina Tarheels.

Here is what you need to know ahead of the games.

How are the teams selected?

The winners of the post-season tournaments in each of the 32 Division 1 basketball conferences receive what is known as an automatic bid into the March Madness national tournament.

The NCAA selection committee then invites 36 teams that are not automatic qualifiers to join.

How many teams are participating?

Sixty-eight teams will take part in the single-elimination tournament. But before the first round begins, four teams are cut in what is called the “First Four”: a play-in competition that officially kicks off the tournament, starting Tuesday.

“The First Four consists of eight teams — the four lowest-seeded automatic qualifiers, and the four lowest-seeded at-large teams,” the NCAA explains on its website. Those rankings are determined by the NCAA Division I Men’s Basketball Committee, which numbers the teams from one to 68.

Once the First Four is complete, 64 teams proceed to the first round of the tournament, starting on Thursday. Matches are scheduled for several US states, including Florida, California and New York.

What is a bracket?

After ranking the teams, the NCAA selection committee puts together what is known as the tournament bracket.

The bracket is essentially the March Madness schedule: It lays out the opening round match-ups according to rank and geographic location. (The tournament is divided into four regions: South, Midwest, East and West.)

These match-ups, in turn, determine the path each team will need to take to reach the championship game.

In 2022, more than 36 million people said they intended to fill out a bracket, with predictions for which teams they hoped would proceed in the tournament, according to the data firm Statista.

There are two days left to complete one for this year’s tournament.

THE BRACKET 🙌#MarchMadness pic.twitter.com/HZYnwD3s3x

— NCAA March Madness (@MarchMadnessMBB) March 12, 2023

Why is the tournament called March Madness?

According to the NCAA, the moniker was first used in 1939 — the same year that the inaugural Division 1 men’s basketball tournament was held — by an Illinois high school official named Henry V Porter.

“But the term didn’t find its way to the NCAA tournament until CBS broadcaster Brent Musburger (who used to be a sportswriter in Chicago) used it during coverage of the 1982 tournament,” the association says.

“The term has been synonymous with the NCAA Division I men’s basketball tournament ever since.”

Who are the teams to beat this year?

Four teams are currently ranked first in their respective regional divisions: Kansas, Alabama, Houston and Purdue.

Oddsmakers agree with the NCAA selection committee that the No 1 seeds are the favourites — Houston at plus-500, Alabama at plus-800, Kansas at plus-1,000 and Purdue at plus-1,200.

According to CBS Sports, “a No. 1 seed has won the NCAA Tournament bracket in six of the last seven years”.

Are any surprises expected?

Part of the fun of March Madness are the unexpected showings and David-versus-Goliath moments that the tournament produces every year. And most experts wager that 2023 will be no exception.

“We know there will be upsets,” ESPN’s John Gasaway and Matt Eisenberg recently wrote as they unveiled their “Giant Killers” model, which looks at potential upsets in games where teams are separated by at least five seed points.

According to their calculations, the No 12 Virginia Commonwealth University (VCU) Rams have the highest odds of an upset, with a 43 percent chance to beat the No 5 team Saint Mary’s Gaels in the first round.

“A classic 12-over-5 surprise. Or would it be? The model gives VCU something close to a coin-flip chance against Saint Mary’s,” Gasaway and Eisenberg said.

CBS Sports also predicted that the 10th-seeded University of Southern California Trojans will defeat No 7 Michigan State in the first round of the East region.

When are the men’s semifinals and championship games?

The last four teams standing will face off in the semifinals — known as the Final Four — on April 1 in Houston, Texas. If they win, they earn a spot in the championship game on April 3.

Does the NCAA also host a women’s tournament?

Absolutely. On the women’s side, the top four seeds in this year’s competition are South Carolina, Indiana, Virginia Tech and Stanford.

The South Carolina Gamecocks are a heavy favourite to become the first repeat winner in the women’s tournament since 2016, when the University of Connecticut notched its fourth straight national championship.

How can I watch?

Every game of the women’s tournament will be available on ESPN’s networks or streaming, with fans encouraged to navigate to the “Watch” tab on ESPN’s sites.

Every game of the men’s tournament will be aired on US television, either on CBS, TBS, TNT or TruTV and their digital platforms. CBS will carry the Final Four semifinals and national title game this year.

March Madness is also available on other channels and streaming services internationally, including TSN in Canada and Kayo Sports and Foxtel in Australia.