The game of squash is played in a closed area surrounded by four walls (the front wall, 2 side walls & the back wall) and the players/teams hit the ball onto the front wall on alternate basis and are allowed to move anywhere within the closed area without obstructing each other. The aim of the game is score a point by striking the ball in such a manner that the opponent is unable to return the ball to the front wall before the ball bounces twice off the court. Safety and fair play are the two most essential elements attached to the game of squash.

Regulation lengths are as follows:

• The length of the court is 9.75 metres and the width of the court is 6.4 metres. The clear height above the surface of the court is 5.64 metres.
• The short line is 5.44 metres from the front wall and half court line runs parallel to the side walls till the back wall starting from the short line. 
• The service line is marked on the front wall at a height of 1.78 metres from the surface of the court. 
• Two service boxes of 1.6 metres X 1.6 metres are marked on the surface of the court. Each service box is formed by the short line, one side wall and two other lines.
• The front line (front out line) is market on the front wall at a height of 4.57 metres and the back line (back out line) is marked on the back wall at a height of 2.13 metres. The side wall lines connect the front line and the back line.
• The height of the tin from the surface of the court on the front wall is 0.48 metre & the tin must not project from the front wall by more than 45 mm. 
• All lines are 50 mm in width and all the lines form area of the court.  

The various lines on the squash court are defined as follows: 

Service line: It is the line that runs along approximately the centre of the front wall and the ball should touch above this line during the serve.

Short line: It is the line behind which the players need to stand & deliver service the served ball should land behind the short line on the opposite half of the court.  

Front line, back line & side lines: The front line and back line defines the upper boundary beyond which the ball can’t touch during a rally or it is deemed out, otherwise. The side lines are the lines marked on the side walls that join the front line and the back line.

Half court line: It is the line that divides the rear half of the squash court and during the serve, the player receiving the service should remain on his/her side of the half court and behind the short line.

Right & left quarters: The half court line & short line divide the rear of the court into areas called left and right quarters.

Ball: The squash balls used for various tournaments vary from single dot to double dot balls depending upon temperature, atmospheric conditions & playing levels. The ball is made of two pieces of rubber compound, that are glued together to form a hollow sphere and are polished with a matte finish. The ball specifications are as follows: 

• The diameter of the ball should be in the range of 39.5-40.5mm with weight in the range of 23-25 grams. 
• The speed of the ball may vary from super slow, slow, medium and fast while the rebound resilience vary from 17-12% at a temperature of 23 degree C. 

Racket: The rackets used in the game are made up of Kevlar, boron, graphite or titanium and the strings are made up of synthetic material (gut, nylon or any other substitute). The racket should be strung and designed in such a way that the playing characteristics are identical on both the faces. The major specifications are as follows: 

• The allowed length of the racket is 686 mm and the allowed width is 215 mm with strung area of not more than 500 sq. cm.
• The maximum allowed weight of the racket is 255 grams.

A singles match comprises of two players while a doubles match comprises of four players without any substitution.

Before the start of the play, a spin of racket/coin spin is conducted and the winning side has the right to serve from either the right side or the left side service box.

A match consists of best of 3 of 5 games or more depending upon the level of competition. For each game, the first team to reach 11 points wins the game, however the game must be won by at least a two point difference over the opponent’s score. A point is scored after each ball is put into play.

The service shall be delivered in the following manner,

• Before the serve, the server should stand with at least one foot on the floor within the service box. The ball can be served from whichever service box the server elects and thereafter alternatively until the service is lost or until the end of the game.
• To deliver a serve, the server should project the ball by hand into the air and should strike it with the racket before it touches the ground. The player is allowed to use only one arm along with racket for projection.
• For the serve to be deemed as correct, the server should serve the ball onto the front wall above the service line and below the front line (out line) before it touches any other part of the court such that on its rebound it first strikes the floor, but not touching, the lines of the opposite service court, either before or after touching any other wall or walls within the playing court.

Second Serve: In case the first serve is a fault then the player is allowed to serve again from the same side half.

For a singles match, 

• The server has the right to choose the side to serve from after winning the spin of racket. If the server wins sequential points, then he/she has to alternate between the serving boxes while serving. 
• In case the receiver wins a point, then he/she has the right to choose the serving side and alternates between serving boxes while winning sequential points.

For a doubles match, 

• Both teams must indicate their order of serving which must remain same throughout the match. Similarly, at the beginning of the match each team nominates one player to receive service from the right side of the court & the other from the left side and each player receives service from that nominated side throughout the game. 
• The teams are allowed to change receiving side at the start of the new game. 
• During a rally, the nominated receiving players have to hit the ball in their respective quarters and it must not be changed throughout the game.

At the commencement of the second and each subsequent game, the player/team that won the previous game serves first.

A let is where the rally is played again and it is allowed when,

• a player stops for safety reasons
• the incoming striker suffers accidental interference who otherwise would have returned the ball
• the result of the rally is undecided or a shot in it has been appealed by any of the player & is undecided
• if the officials are undecided or players can’t agree whether let or a stroke should be awarded

A stroke is called when the rally is awarded to the player as a penalty against the opponent. A stroke is given when, 

• the incoming striker is in position to win the rally but suffers interference due to outgoing player
• the incoming striker would have struck the opponent with the ball going directly to any part of the front wall
• the outgoing player did not make every effort to clear way for the incoming player

A serve that hits the service line, or the short line, or the half court line, or any line bounding the top of the court, is considered as a fault.

• Depending upon the level of the competition, player can ask/appeal the match officials to review let or stroke decisions, once per game. 
• In case the official call after the review call is deemed correct then the player looses the review and he/she is not allowed to make any appeal throughout the duration of the game.
• However, in case the appeal made by the player is correct then he/she retains the review.

The designated match officials for the game of squash are as follows:

• Referee
• Marker