The ancient law in the Orient was similar to the law of Hamurabi, "an eye for an eye, a tooth for a tooth", and was rigorously enforced even if death was caused accidentally. 
In this type of environment, and since the present system of free sparring had not yet been developed, it was impossible for a student of the martial arts to practice or test their individual skill of attack and defence against actual moving opponents.

Individual advancement was certainly hindered untill an imaginative practitioner created the first patterns.

Patterns are various fundamental movements, most of which represent either attack or defence techniques, set to a fixed and logical sequence.

The student systematically deals with several imaginary opponents under various assumptions using every available attacking and blocking tools from different directions. Thus pattern practice enables the student to go through many fundamental movements in series, to develop sparring techniques, improve flexibility of movements, master body shifting, build muscles and breath control, develop fluid and smooth motions, and gain rythmical movements.

It also enables a student to acquire certain special techniques which cannot be obtained from either fundamental exercises or sparring. In short, pattern can be compared with a unit tactic or a word if fundamental movement is an individual soldier's training or alphabet. Accordingly pattern, the ledger of every movement, is a series of sparring, power test, feats and characteristic beauty.

Though sparring may merely indicate that an opponent is more or less advanced, patterns are a more critical barometer in evaluating an individuals technique.

The Reason for 24 Patterns

The life of a human being, perhaps 100 years, can be considered as a day when compared with eternity. Therefore, we mortals are no more than simple travelers who pass by the eternal years of an eon in a day. It is evident that no one can live more than a limited amount of time. Nevertheless, most people foolishly enslave themselves to materialism as if they could live for thousands of years. And some people strive to bequeath a good spiritual legacy for coming generations, in this way, gaining immortality. Obviously, the spirit is perpetual while material is not; therefore, what we can do to leave behind something for the welfare of mankind is, perhaps, the most important thing in our lives.

Here I leave Taekwon-Do for mankind as a trace of man of the late 20th century. The 24 patterns represent 24 hours, one day, or all my life. The name of the pattern, the number of movements, and the diagrammatic symbol of each pattern symbolizes either heroic figures in Korean history or instances relating to historical events.

General Choi, Hong Hi

Reproduced, with permission, from "Taekwon-Do (The Korean Art of Self Defense)" also known as "The Condensed Encyclopedia." 
Fifth Edition 1999, All rights reserved
Copyright 1988, 1991, 1992, 1995, 1999 General Choi, Hong Hi.