Soft tennis is essentially tennis with a softer, lighter, inflatable ball and, optionally, lighter, more loosely strung racquets. Soft tennis is most popular in Japan, where it was first played in 1884 and now comprises roughly 40% of the tennis played. It's also popular in Korea and Taiwan and growing all over the world, with some two dozen national federations and associations from Peru to Hungary.
The main attractions of soft tennis are a gentler learning curve and longer rallies. Most of these advantages come from the soft-tennis ball, which weighs 30-31 grams, just over half the 56-59.4 grams a regular tennis ball weighs, but with the same diameter as a regular tennis ball, 6.6 cm. With half the weight and the same diameter as a tennis ball, the soft-tennis ball has far greater air resistance, so it flies more slowly, making it easier to run down, with more time to execute a stroke and less chance of hitting it too far. This makes the game easier to play, especially for beginners, and better exercise at all levels, because rallies last longer.
The lighter soft-tennis ball is also much easier on the arm, as both the shock and the torsion produced in racquet-ball collisions decrease with decreased ball weight and speed. This benefit is offset slightly by the lighter racquets, around 8.5 ounces, usually used for soft tennis, but many regular tennis racquets are equally light, and soft-tennis racquets are strung looser, which helps reduce the effects of shock. Many players use heavier tennis racquets for soft tennis; the rules don't specify racquet weights.
The most unique characteristic of the ball is its air valve; it can be inflated and deflated to change its liveliness. The soft-tennis rules state, "The ball shall have a bound of between 65 and 80cm when dropped from a height of 1.5m upon the Court on which a match is played." That large range of allowed bounds (bounce heights) gives players (or tournament directors) considerable choice about how they want the ball to play, as lower air pressure will reduce both bounce height and the speed with which the ball leaves the racquet at a given swing speed. It's also notable that, in contrast to tennis, where balls are tested by being dropped onto concrete at a specific temperature, soft tennis standards call for testing on whatever court surface is being used, thus reducing the effects of court surfaces and weather conditions, at least in terms of bounce height.
Most of the rest of the rules of soft tennis are the same as regular tennis. Here are the more significant exceptions:
- The net is the same height, 1.07m or 3'6", all the way across the court; it's not 6" lower in the middle as in regular tennis.
- A match in singles consists of a single set completed by winning four games (best of seven). A doubles match is won with five games (best of nine). The number of games in a match might be so much fewer than in regular tennis because soft-tennis points are expected to last much longer.
- In soft tennis doubles, the serving rotation between teams is the same as in regular tennis, but the partners on a team take turns serving two consecutive points throughout the game.
- Instead of tie-breaks, soft tennis uses a "final game" at 3-all in singles or 4-all in doubles. In the final game, singles players or doubles teams take turns serving two points at a time, and they change ends after the first two points and then after every four.
Soft Tennis racquets, balls, ball pumps, and air gauges are available from the manufacturer, Kenko Soft Tennis, and from other online retailers.