Kendo is a Japanese martial art that involves practitioners using bamboo swords called "shinai" for sparring and practice. While kendo strikes can cause some discomfort and may leave temporary marks or bruises, the intent of kendo is not to cause severe pain or injury.

The shinai used in kendo are designed to be flexible and absorb the impact of strikes, reducing the risk of serious injury. They consist of several bamboo slats held together by leather or string, and the striking surface is cushioned with a protective covering. The emphasis in kendo is on proper technique, control, and discipline, rather than inflicting harm.

That being said, it is still possible to experience some pain or discomfort when struck by a shinai, especially if strikes are delivered with force or target sensitive areas of the body. Safety precautions are taken in kendo practice to minimize the risk of injury, such as wearing protective gear, including a helmet (men), body armor (do), gloves (kote), and a groin protector (tare).

In a controlled and supervised environment, with adherence to proper technique and guidelines, the risk of serious injury in kendo is relatively low. However, like any martial art or contact sport, there is always a level of inherent risk involved. It is important to train under the guidance of a qualified instructor, follow safety protocols, and practice good sportsmanship to minimize the potential for injury.