Kendo was established during the Edo Period and is an one-on-one sport emphasizing courtesy. It uses a bamboo-made sword called shinai, and the players wear protective guards called men, do, kote and tare on top of cotton clothing called dogi and hakama. Despite the heavy gears on most parts of the body, kendo is usually fought bare feet.
The sight of the match with competitors wearing a full set of kendo outfit and wielding the shinai resembles the Japanese samurai - a now-lost species with impressive gears and flashing swords - and the player population grows steadily as its popularity spreads widely across the ocean.
Points are gained when one jabs the other in any of the effective jab points (meaning that not all jabs are effective), and a successful jab is counted as ippon (=1 point). A maximum of three rounds are fought for one match, and the one who gains nihon (2 points) first becomes the winner of the match (however, details of the rules are far more complicated).
Like this, kendo is a sport based on a set of rules, but more than it is a sport it is an ultimate martial art with austere principles.
For instance, players are forbidden to make pose or to let out a happy cry right after the judge's call of ippon. If the player does so, that ippon will be taken back. One can say that establishing these rules as rules may be a characteristic of a sport, but the reason behind it deeply roots in the origin of budo, martial arts, itself.
Now let us once more go over the basic definitions of budo.
Article No.1 of Budo Charter set by Japan Budo Association describes as the following: "The principle of budo lays in the fostering of a promising figure by full development of insight and moral personality through physical and mental training of budo skills."
Additionally, the definition of budo in a Japanese dictionary is stated as follows: "Budo is the way ("do") of the martial arts ("bu")." "Martial arts skills ("bujutsu")" on the other hand, "are the skills warriors ("bushi") acquire for practical battles". The differences between budo and bujutsu are significant notions in understanding budo.
The sword for kendo is referred to as katsuninken, a sword for skill acquisition and mental discipline which had shifted from the former setsuninken, the kenjutsu's sword which was nothing but a means of manslaying. Here, you can also see the differences between budo and bujutsu.
(The original meaning behind the transformation of setsuninken to katsuninken is said to be to brush up the sword skills to save people instead of brushing up those to kill people.)
In another word, kendo is the way to self-acquire the "law of ken (sword)" through battles of ken, and to study kendo means to study the law of ken.
Or to cut it down to the point, the core emphasis of studying kendo is to learn the spirit of the bushi which is behind the "law of ken". And to learn kendo through austere manners of kendo can be perceived as one of the means to study such spirit.
This is why the goal of kendo is commonly described as a "way of human formation".
Kendo is more than a sport. It is a budo training one's body and soul to form moral figures.