The last time an Australian Football League game was played at Melbourne Cricket Ground, in late September, 100,014 fans were on hand to see Richmond win its 12th championship.

There were 100,014 fewer fans in the stands at MCG on Thursday as the AFL kicked off its season with a closed-door match between the defending champions and Carlton. Despite the growing number of coronavirus cases in the country — 709 as of Thursday, up 141 from the day before — and new travel restrictions, Prime Minister Scott Morrison said the government would leave it up to the AFL and the National Rugby League about whether to start their seasons on time.

On Wednesday, AFL officials held a marathon teleconference with team executives and decided to start the season with a few adjustments. Games will be played without fans present for the foreseeable future, the season has been shortened from 22 to 17 games, and quarters have been cut down from 20 minutes to 16 minutes to reduce player fatigue in the event that teams have to play more than once a week to finish the season. Plus, the season will be suspended if any player tests positive for the coronavirus.

On Monday, the AFL players’ union polled its membership about starting the season, with 88 percent voting in favor.

Given that the sport is one of the few still playing amid the pandemic, global interest could spike. Alicia Loxley, an Australian news anchor and reporter, noted this on Twitter:

For American fans who perhaps last watched an AFL match in the nascent days of ESPN, here’s a brief primer on the basic rules.

— Each team has 18 players on the field, and the objective is to kick the ball through sets of four posts at each end. Kick the ball between the two taller posts in the middle (the goal posts), and a team gets six points for a “goal.” Kick the ball between one of the middle posts and a shorter post to the side (the point post) and a team gets one point for what is called a “behind.” One-point behinds also are awarded if the ball hits or goes above a goal post, or if the ball goes between the goal posts despite not being kicked by the attacking team (for instance, if it comes off the hands of either team or is kicked by the defending team).

— The final score of Thursday’s season opener was Richmond 16.9 (105), Carlton 12.9 (81). That means Richmond kicked 16 goals (96 points) and scored nine behinds (nine points) for 105 total points. Carlton had 12 goals and nine behinds for 81 points. The team with the most points wins, though that means the team that scored fewer goals may sometimes be the winner. A match is considered a draw if each team scores the same number of points.

— The ball may be advanced by either kicking it to a teammate or punching it with the fist of one’s hand. If a player catches a ball kicked from at least 15 meters away (by either team) without the ball touching the ground or being touched by an opposing player, it’s considered a “mark” and the player who catches it gets a free kick or hand pass. Players may also run with the ball, though they are required to bounce it off the field or touch it to the field with both hands at least once every 15 meters.

— Defending teams can tackle the ballcarrier, but no contact is allowed above the shoulders or below the knees. If the attacking player with the ball is tackled without making an attempt to get rid of the ball or makes an illegal attempt to get rid of the ball, the defending team is awarded a free kick. The player who is tackled must immediately attempt to dispose of the ball legally to a teammate; if he takes too much time, a free kick is awarded to the opposing team.