What are the rules for doubles in table tennis?

• Hitting order: the four players strike in a fixed sequence. Hitting out of turn loses the point.
• The serve bounces in the server's right half-court and then the receiver's right half-court. The centre line counts as part of each right half.
• After the serve the ball may land anywhere on the table.
• Each change of service: the previous receiver serves, and the previous server's partner receives.
• At the start of each game the serving pair chooses its first server. In the first game the receiving pair chooses its first receiver. In later games the first receiver is the player who served to that server in the game before.
• In the last possible game, when one pair first reaches 5, the pairs change ends and the receiving pair swaps its order of receiving.
• A warning or penalty for one partner applies to the pair.

Taking turns is what makes doubles a team game: neither partner can take every shot, and both must keep moving out of each other's way.