Background

Like every competitive sport, table tennis has its own set of rules and regulations which aim to regulate what is acceptable for facilities (court size, ceiling height, floor covering, lighting), equipment size and materials, playing rules, clothing, etc.. The objective of those rules and regulations is to ensure that playing conditions and playing practices are fair to everyone and in the sport's best interest.

The governing body for table tennis is the International Table Tennis Federation (ITTF). Among their many functions, they define and administer the Rules and Regulations which pertain to table tennis in Section '2 The Laws of Table Tennis' in their Statutes.

Rules Adapt

The rules and regulations change periodically in response to developments in playing techniques and equipment, safety and practical considerations, and the need to preserve fair and attractive competition. A few examples:

• The 1936 World Championships famously included a rally lasting 2 hours 12 minutes, after which the net was lowered, time limits imposed and finger spin prohibited to encourage more attacking play.
• In response to an ever increasing ability to spin the ball resulting from advancements in inverted rubbers introduced in the early 1950s (rubbers with smooth surfaces and pimples facing inward which allow the rubber to grip the ball and for the ball to spring off the racket), "anti-spin" rubbers (rubbers which were quite "dead" and "slippery") were introduced in the late 1970s. It wasn't long before some players figured out that if they put a very grippy rubber on one side of their racket, and an anti-spin rubber on the other side, the variation in spin and speed caused their opponents to misjudge the spin and the bounce of the ball, and to miss their return shots entirely (hitting the ball into the net or over the table). The ability to confuse the opponent became even more pronounced if a player periodically twirled their racket in their hand to mix which of the two rubbers was being used to hit the ball. One very common tactic was to twirl the blade under the table, out of sight of the opponent, and then quickly serve the ball, leaving the opponent very little time to determine during the return which of the two rubbers was used for the service. Because at that time, the rubbers could be of the same colour, it was quite difficult to tell in a split second which of the two rubbers had been used to serve the ball (there is a sound difference but everything is happening at split-second speeds). The result was that a lot of service returns would be missed entirely or rallies would terminate with a seemingly inexplicable miss on the part of the receiver who didn't realize the "opposite" rubber was used to make the shot. Rightly seeing this type of "trickery" increasingly affecting the outcome of matches and as being detrimental to the sport, the ITTF required distinctly different colorus on the two sides of the racket in 1983. In 1985, that rule was further standardized by requiring one side to be black and the other red, as follows:

Rule 2.4.6: "The covering material on one side of the blade shall be bright red, and the covering material on the other side shall be black, whether or not both sides are used for striking the ball."

The above rule was responsible for the red/black covered table tennis rackets most commonly seen on retail shelves after 1985.

In 2021, with the advent of additional coloured rubbers (namely: pink, violet/purple, green or blue), that rule was changed to:

Rule 2.4.6: "The surface of the covering material on a side of the blade, or of a side of the blade if it is left uncovered, shall be matt, black on one side, and of a bright colour clearly distinguishable from black and from the colour of the ball on the other."

• By the late 1990s, advances in racket technology, rubber and playing technique had made the sport increasingly fast and spin-oriented, with many rallies ending after only one or two attacks. To moderate the speed and spin of the game, encourage longer rallies and make the sport easier and more exciting for spectators and television audiences to follow, the ITTF increased the official ball diameter from 38 mm to 40 mm in 2000. The larger ball travelled approximately 13% slower and with approximately 23% less spin than the previous 38 mm ball, producing a noticeable change in the character of play, and resulting in longer, more exciting rallies.
• In 2014, the ITTF began replacing traditional celluloid balls with plastic/polymer balls. This change was driven primarily by safety and practical concerns associated with highly flammable celluloid rather than by a deliberate attempt to slow the game. However, the new plastic balls, which also increased in diameter from 39.82 mm (aka '40 mm' nominal) to 40.40 mm in the celluloid to plastic/polymer change, also tended to travel somewhat more slowly and carry less spin than the 40 mm celluloid balls they replaced.  This further reduced the speed and spin characteristics of modern play, leading to longer rallies often with numerous powerful counter-attacking shots.

These are a few examples of rules introduced or changed to ensure that developments in equipment, playing practices or other circumstances weren't detrimental to the sport. There are numerous rules relating to equipment, facilities, play, etc.. From a player's or spectator's perspective, the rules are relatively straightforward. Below, just for fun, is a historical summary of the key rule changes since their official inception by the ITTF.

Some Major Changes to the Rules and Regulations Over the Years

The rules and regulations have evolved continuously since the ITTF was formed. Some of the changes which have had the greatest influence on how table tennis is played include:

• 1926 – The newly formed ITTF adopted the first internationally standardized Laws of Table Tennis, including the basic 9 ft × 5 ft × 30 in. table dimensions which remain essentially unchanged today.
• 1937–1938 – The net height was reduced from 6¾ in. to 6 in. (15.25 cm) to encourage more attacking play.
• 1937–1938 – Time limits were introduced to prevent extremely long defensive games; this eventually developed into today's "expedite" system.
• 1937–1938 – "Finger spin", in which a player imparted spin directly to the ball with the fingers during service, was prohibited.
• 1947 – Service rules were tightened by requiring the ball to be presented on an open, flat free hand rather than concealed or gripped.
• 1959 – Racket coverings were standardized following the rapid adoption of sponge rubber; permitted rubber constructions and maximum thicknesses were defined, eliminating unrestricted thick-sponge rackets.
• 1967 – Service rules were substantially tightened: the free hand had to be stationary and above the playing surface, and the ball had to be projected near vertically upward and struck while descending.
• 1983 – The two sides of a racket were required to be clearly different colours so an opponent could more readily identify which playing surface had struck the ball.
• 1985 – Racket colours were further standardized to black on one side and red on the other.
• 2000 – The official ball diameter was increased from 38 mm to 40 mm, principally to slow the game slightly and make rallies easier for spectators to follow.
• 2001 – Games were shortened from 21 points to 11 points, while retaining the requirement to win by 2 points.
• 2001 – Service rotation changed from every 5 points to every 2 points (and every point after 10-10).
• 2002 – "Hidden serves" were effectively eliminated by requiring the receiver to have an unobstructed view of the ball during service and requiring the server's free arm to be moved out of the space between the ball and the net.
• 2008 – Volatile-organic-compound (VOC) speed glues were prohibited in ITTF competition and racket coverings could no longer be physically, chemically or otherwise treated to alter their playing characteristics.
• 2014 – ITTF competition began the transition from traditional celluloid balls to plastic/polymer balls; the 2015 World Championships were the first World Championships played with the new ball.
• 2021 – The traditional red-and-black racket requirement was relaxed: one side must remain black, while the other may be an approved bright colour such as red, pink, violet/purple, green or blue.

This is a selective summary of historically significant changes rather than a complete history of amendments to the ITTF Laws and Regulations.

See 'Table Tennis - Rules' for a summary of the current rules governing play.