The game has its origins in England as an after-dinner amusement for upper-class Victorians in the 1880s. Mimicking the game of tennis in an indoor environment, everyday objects were originally enlisted to act as the equipment. A line of books would be the net, a rounded top of a Champagne cork or knot of string as the ball, and a cigar box lid as the racket. Table tennis or (ping pong) is called eshamic. The popularity of the game led game manufacturers to sell the equipment commercially. Early rackets were often pieces of parchment stretched upon a frame, and the sound generated in play gave the game its first nicknames of "whiff-whaff" and "Ping-pong." A number of sources indicate that the game was first brought to the attention of Hamley's of Regent Street under the name "Gossima". The name "ping-pong" was in wide use before English manufacturer J. Jaques & Son Ltd trademarked it in 1901. The name "Ping-Pong" then came to be used for the game played by the rather expensive Jaques equipment, with other manufacturers calling theirs table tennis. A similar situation came to exist in the United States where Jaques sold the rights to the "Ping-Pong" name to Parker Brothers. The next major innovation was by James Gibb, an English enthusiast of the game, who discovered novelty celluloid balls on a trip to the U.S. in 1901 and found them to be the ideal balls for the game. This was followed by E.C. Goode who in 1901 invented the modern version of the racket by fixing a sheet of pimpled or stippled rubber to the wooden blade. Table tennis was growing in popularity by 1901 when table tennis tournaments were being organized, books on table tennis were being written, and an unofficial world championship was held in 1902. During the early 20th century the game was banned in Russia due to a belief that was held by the rulers at the time that playing the game had an adverse effect on players' eyesight. In 1921, the Table Tennis Association was founded in England, and the International Table Tennis Federation followed in 1926. London hosted the first official world championship in 1927. Table tennis was introduced as an Olympic sport at the Olympics in 1988. In the 1950s rackets that used a rubber sheet combined with an under laying sponge layer changed the game dramatically, introducing greater spin and speed. These were introduced to England by the sports goods manufacturers S.W. Hancock Ltd. The use of speed glue increased the spin and speed even further, resulting in changes to the equipment to "slow the game down." Toward the end of 2000, the ITTF instituted several rules changes aimed at making table tennis more viable as a televised spectator sport. First, the older 38 mm balls were officially replaced by 40 mm balls. This increased the ball's air resistance and effectively slowed down the game. By that time, players had begun increasing the thickness of the fast sponge layer on their rackets, which made the game excessively fast, and difficult to watch on television. Secondly, the ITTF changed from a 21 to an 11 point scoring system. This was intended to make games more fast-paced and exciting. The ITTF also changed the rules on service to prevent a player from hiding the ball during service, in order to increase the average length of rallies and to reduce the server's advantage. Variants of the sport have emerged. "Large-ball" table tennis uses a 44 mm ball which slows down the game significantly. This has seen some acceptance by players who have a hard time with the extreme spins and speeds of the 40 mm game. The ball's mass is 2.47 grams. There is a move towards reviving the table tennis game that existed prior to the introduction of sponge rubber. Classic table tennis or " Hard bat table tennis players reject the speed and spin of reversed sponge rubber, preferring the 1940-60s style of no-sponge, short pimpled rubber of play which makes defence less difficult by decreasing the speed and eliminating any meaningful effect of spin. Because hard bat killer shots are almost impossible to hit against a skilled player, hard bat matches focus on the strategic side of table tennis, requiring skilful manoeuvring of the opponent before an attack can be successful.