The rules of 4-square are fairly simple.

Players start in the first square (Princess) and work to try to advance to the fourth square (King).
-Players can only advance when someone in a higher square is eliminated In this manner; a person in the 1st square will advance if anybody in the 2, 3, or 4 square is eliminated, however, the 3rd square will only advance if the 4th square is eliminated.
-Every time a player is eliminated, all the lower players move up one square to fill the open spot. The 1st square is filled by the next player in line.
-The eliminated player moves to the back of the line, or, if there is no line, to the 1st square again.

Players are eliminated when any number of errors occur on their part.
-A ball cannot bounce in a player's square twice.
-A player cannot hit the ball into their own square.
-A player must return the ball into another person's square. They are out if they hit outside the squares.
-A player may not hit the ball twice. This includes unintentional hits.
-A player may not hold the ball for any length of time when it is in play. Some hits may be considered "carrying", which is illegal. Beginners will be warned of this, but not penalized unless it persists.

The person at the front of the line is the referee.
-The referee is expected to watch play at all times and make a call when someone is eliminated if it is not obvious, or if there was a controversial end.
-If the referee is not paying attention, or will not make a call declaring one way or another, they may call for a re-do of the round.
-"Integrity", which is the act of callings oneself out for a bad play, automatically trumps the referee's call.
-On rare occasion, two or more players may be out. Depending on the referee and the rules, all 4 players may be eliminated, though this is unlikely.

Players may save another player from elimination.
-If a player cannot return a ball and someone else returns it successfully without being eliminated themselves, the ball is still in play.
-Another player may hit the ball again into the square of their opponent after it has already bounced once in the square. The ball remains in play.

The King receives points for every elimination (though not including their own).
-The King begins receiving points after their first successful square defense.
-The King starts every round by being the server.

All serves are done by the King and are two-hand underhand serves after a single bounce in their square.
-The serve is not to be aggressive.
-The point of the serve is to start play, not to rack up points. A serve may become questionable after several consecutive "Ace"s.
-An experienced player may be eliminated for an incorrect serve, while a newcomer may be given a re-serve.
-If the serve lands out of the squares or inside his/her own square, the King is out.
-A serve cannot be taken out of the air. A repeat offender will be out. A new person will be excused.
-All persons will be outside their respective squares at the time of the serve.

The game is over when a King acquires 15 points.
-The points of each round roll over. A person may be king and acquire 13 points in one round before being eliminated. The next time they take King square they retain those 13 points (unless the game ended between reigns) and only need 2 more points to win the game.
-Common courtesy says that the King announce his/her score before every round, though it is not required. It is expected to announce when they are near a win.
-Game point is at 14 points and must be announced so that all players know.