Most people familiar with martial arts are also familiar with breaking demonstrations. The idea is that the ability to break a board, brick, or concrete slab translates into striking ability in a fight. A skilled practitioner of this art will be able to perform impressive breaks, but there are some people who try to make their power look greater than it is.
For example, some martial artists will break a stack of many concrete slabs at an iron palm demonstration, but they put spacers between each piece of concrete. By doing this, when the first concrete slab is broken, it breaks and smashes into the next slab which helps to break it, so not as much force is required from the strike in order to break them. That is not to say the person isn’t powerful, but breaking with spacers is easier than breaking without spacers. In other words, breaking 5 bricks that are placed directly on top of each other is more impressive than breaking 5 bricks with spacers between them.
An advanced iron palm breaking technique is to selectively break an individual brick from within a stack of many bricks. The student is usually taught first how to break the bottom brick in a stack of two bricks, and then progresses to a stack of 3 bricks and learning to break just the middle brick or just the bottom brick. The skill required to do this is vastly different from the ability to break all the bricks in a stack. It is said that very high level practitioners can choose to break any brick in a big stack of bricks, or they can break every brick except for a selected brick in a large stack.
When breaking, especially in the beginning stages of training, it is usually a good idea to cover the brick with a towel to protect your hand from small chips or jagged bits that may be on the surface. A towel will not dampen the power transfer, but will protect the hand from cuts and abrasions.
It is important not to attempt to break too early. The martial arts student must wait until he has achieved a sufficient level of conditioning first. Attempting to break too early can result in injuries which may set back the martial arts training.