Although it is important to study and train for skill in techniques, for the man who wishes to truly accomplish the way of Budo, it is more important to make his whole life in training and therefore not aiming for skill and strength alone, but also for spiritual attainment.

Mas Oyama

Tameshiwari, the art of breaking wood, tile, bricks and stone with the fist or the bare foot, is not a purpose of karate, but rather serves as a barometer of acquired strength and technique. It is useful for this purpose because in kumite (sparring) you must never actually touch the opponent for fear of causing extreme physical injury.

"Karate School" by Mas Oyama