Katas are used in varying forms of martial art, but what 'really' is a Kata? Simply put, it is a series of specific movements, carried out in a set form. Kata itself is a Japanese word, however this method of teaching / learning is by no means solely Japanese.

In Kung-Fu and Tae-Kwon-Do (along with many other martial arts I shall not name specifically), the same idea is used only they are called 'sets' or 'patterns'.

So why are they so popular? After all, modern styles such as Brazilian Jiu-Jitsu does not use them; neither do western styles of fighting such as wrestling or boxing. Or do they?

How many people watched one of the Rocky films for instance (as cheesy as some might find them) or any other boxing films? You will not see some Buddhist monk moving through a sequence of movements in a slow spiritual manner, but do you see a kata?
In short, YES. Boxing katas tend to follow a much simpler approach, for instance with one person holding two hand pads and the other punching:


This sequence would then be repeated in that exact format maybe 20-40 times, is this not a kata?

The reason the boxer and Karateka/Jiu-Jitsuka alike train with this repetition is simple. The more you do something the better you get, also and more importantly the more familiar and adaptable that movement becomes to you.

Most people however do not see the boxer's repetitions and a Japanese Kata being the same thing, the reason being there is often a crucial difference.

A Kata embodies more than merely a series of physical movements, 'Doctor Smoke' (kata) phrased this point very well above "Done correctly, kata can be used to attain a higher understanding of the moves being performed, and alternate uses of the moves will suddenly become apparent."

To take this to the next level, Kata can also be used as a form of self-reflection or meditation. Once a kata is well rehearsed, an exponent can carry out the kata almost without conscious thought.
A person can then become aware of is every single movement within there own body, gaining a greater knowledge and appreciation of themselves and with this, a clear mind able seek to understand otherwise clouded issues in the world around them.