Futsal is a variant of soccer that is played on a smaller, hard court with specific rules. Here are some of the key rules of futsal:

• Team size: Each team consists of five players, including a goalkeeper. Substitutions are unlimited and can be made "on the fly," meaning players can switch out without stopping the game.

• Ball: A smaller, low-bounce ball designed specifically for futsal is used. The ball size is typically between size 3 and size 4.

• Court size: The court dimensions can vary, but it is usually between 25-42 meters in length and 16-25 meters in width. The court is marked with lines, including boundary lines, goal lines, penalty area, and a halfway line.

• Kick-ins: Instead of throw-ins, kick-ins are used to restart play from out-of-bounds. The player taking the kick-in must place one foot on the touchline or outside the court and kick the ball into play.

• No sliding tackles: Sliding tackles are not allowed in futsal. Players are not permitted to slide on the ground to gain possession of the ball or tackle an opponent.

• 4-second rule: For restarts such as kick-ins, corner kicks, or free kicks, the player must release the ball within 4 seconds of taking possession of it.

• Goalkeeper restrictions: The goalkeeper is limited to playing with their feet within their designated penalty area. The goalkeeper cannot touch the ball with their hands outside the penalty area.

• Accumulated fouls: Each team is allowed a limited number of fouls (usually 5) per half. After that limit is reached, any subsequent fouls result in a direct free kick for the opposing team from a marked spot on the court.

• No offside: Unlike traditional soccer, there is no offside rule in futsal. Players are not penalized for being in an offside position.

• Continuous play: The game is played in two halves, typically with a running clock. The clock stops only for time-outs or during injury or equipment delays.

These are some of the basic rules of futsal, but it's important to note that specific rules may vary depending on the league or competition you are playing in. It's always a good idea to familiarize yourself with the rules of the specific futsal league or tournament you are participating in to ensure fair play and compliance with the regulations.