There are two principal ways of practicing Judo: Kata and Randori. Kata, which literally means "form" is practiced following a formal system of prearranged exercise, while Randori, meaning "free practice" is practiced freely. Through Kata practice, trainees learn the principles of techniques.
In the Kodokan, the following nine Katas are mainly adopted;
1. Nage-no-Kata (Forms of Throwing)
Three representative techniques are chosen from each of five Nage-wazas: Te-waza, Koshi-waza, Ashi-waza, Ma-sutemi-waza and Yoko-sutemi-waza.
2. Katame-no-Kata (Forms of Grappling or Holding)
Five model techniques are chosen from each of three Katame-wazas: Osaekomi-waza, Shime-waza and Kansetsu-waza.
3. Kime-no-Kata (Forms of Decisive techniques)
This is to learn the techniques for serious combative fight. It consists of the techniques in a kneeling position (Idori, 8 techniques) and in a standing position (Tachiai, 12 techniques).
4. Ju-no-Kata (Forms of Gentleness & Flexibility)
This is an expressive, gymnastic composition of the methods of attack and defense in a series of slow and moderate actions. It consists of three components, Dai-ikkyo (Set 1), Dai-nikyo (Set 2) and Dai-sankyo (Set 3), each of them has five techniques.
5. Kodokan Goshin-jutsu (Forms of Kodokan Self-Defense)
This consists of an "Unarmed section" and a "Weapons section". The "Unarmed section" consists of twelve techniques while the "Weapons section" consists of nine techniques.
6. Itsutsu-no-Kata (Forms of "Five")
These forms express the mechanism of attack and defense in an elevated way. It consists of five sequences of movements that artistically express the power of nature.
7. Koshiki-no-Kata (Forms of Classics)
Kano Shihan highly evaluated the forms of Kito-ryu Jujutsu as they represent the essence of attack and defense. Therefore, he left the forms as Kodokan Koshiki-no-Kata, with little changes. It consists of 14 Omote (front) techniques and 7 Ura (back) techniques.
8. Seiryoku-Zenyo-Kokumin-Taiiku (Forms of Maximum- Efficiency National physical education)
It contains both aspects of physical education and martial arts and has forms of attack and defense. It consists of 8 movements of Tandoku-renshu (Solo practice) and 9 movements of Sotai-renshu (Duo practice).