Though karatedo has become a kind of martial art sport nowadays, the destructive power of certain attacking techniques is so great that it cannot be overlooked in our normal practice. Therefore personal safety has to be ensured in the practice of sparring. Whether an attacking technique could cause injury to the opponent depends on its power and the depth of impact. If we intentionally control the power to avoid causing injury to the opponent, the meaning and value of sparring practice will be defeated. Therefore we have to apply “Sundome” (inch-stop) to control the depth of impact, and hence to ensure the safety of our partner. This is the purpose of Sundome.

In general, people may consider Sundome as stopping the attacking technique one inch before hitting the opponent’s body. In fact, trained people can receive relatively powerful hits on their muscled areas, such as the abdomens and chests; whereas some sophisticated areas, such as the heads and necks, are very susceptible to injury. Therefore we have to apply different degree of Sundome to different areas of the body. Simply speaking, a good Sundome means to stop an attacking technique one inch before it will cause an injury to the opponent. This expression demonstrates the true spirit and meaning of Sundome – inch-stop.

When Sundome can be correctly executed, powerful attacking techniques can be applied; thus the meaning and value of sparring practice can be fostered.