What Is Judo? Jigoro Kano, Kodokan Judo, Belt Ranks, and the Principles Behind the Gentle Way

The answer to what is Judo begins with the Japanese characters 柔道. Ju means softness, flexibility, or yielding, while Do means a way or path of self-cultivation. Judo is therefore a martial art, a sport, and a disciplined method for developing the whole person.

The word gentle does not mean weak. In Judo, gentle means using the right angle, rhythm, balance, and timing instead of forcing strength against strength. If someone pushes, you may pull. If someone pulls, you may follow and redirect. When balance is broken, a throw or hold can happen with far less wasted effort. This is why Judo values understanding the body more than meeting force head on.

Jigoro Kano was the founder of Judo and an important educator in modern Japan. He was born in 1860, as Japan was moving into the Meiji era, a period when the country rapidly reformed its education, military, and society. As a boy Kano was not physically big. He took up Jujutsu to build his body and to defend himself, but what set him apart was asking for the reasons behind each technique rather than only memorizing moves. He studied classical Jujutsu, including Tenjin Shinyo-ryu and Kito-ryu, then reorganized what he learned into a safer and more systematic practice.

When people ask who was Jigoro Kano, the answer is not only a martial arts founder. Kano was an educator who believed martial arts could train health, discipline, intelligence, ethics, and social responsibility.

Kodokan Judo is the original Judo system that Jigoro Kano founded in 1882, based at the Kodokan in Tokyo. Kodokan, written 講道館, can be understood as a place for teaching the way. This matters because Kano did not want to preserve combat techniques only as isolated tricks. He wanted a living method of education.

If you ask what Kodokan Judo is, the answer is the standard foundation of Judo worldwide, in technique, Kata, Randori, the teaching system, etiquette, and philosophy.

For primary historical context, see the Kodokan official site. The International Judo Federation also provides a useful overview of Judo history and its discussion of Judo culture.

Seiryoku-Zenyo means maximum efficient use of energy. In technique, it means not wasting force. In life, it suggests using time, effort, and attention wisely.

Jita-Kyoei means mutual welfare and benefit. Judo requires a partner, so progress depends on trust, safety, and shared responsibility. A strong Judo class is not built by overpowering weaker students; it is built by helping everyone improve.

• Ukemi: safe falling and receiving technique
• Kuzushi: breaking balance
• Tsukuri: fitting into position
• Kake: completing the technique with control
• Randori and Kata: free practice and formal principle practice

Many people begin with the question what do you learn in Judo, and the answer is far more than throwing skill. Judo develops strength, balance, agility, concentration, discipline, emotional control, and confidence under pressure.

Judo helps in close-range situations such as being grabbed, pulled, pushed, held, or knocked off balance. Its strengths are balance, safe falling, controlling someone who has closed the distance, and using the other person's force without trading punches.

Real self-defense, however, is not only technique. A student also needs to understand avoiding situations, asking for help, the law, and leaving when leaving is possible. Judo is an excellent foundation, but it should stay within a framework of safety and responsibility.

What makes judo history interesting is that Jigoro Kano did not build a new art from nothing. He studied Tenjin Shinyo-ryu and Kito-ryu jujutsu, picked out their strengths and reorganised them into a new system. He removed what was too dangerous for repeated practice, added safety principles, and raised the art from jutsu, a technique, to do, a way of developing people.

That is why the question who was Jigoro Kano should not be answered only with "the founder of judo". He is better seen as an educator who used a martial art as a tool to make people stronger, more reasoned, and better able to live alongside others.

The All Japan Judo Federation's material supports this view well. Its content for beginners does not talk only about competition; it covers what learners gain from judo, how to start safely, and ukemi, or falling safely, as an essential foundation before moving on to more demanding techniques.

Read next · Judo ThailandSambo vs Judo vs Jujitsu: What Actually Differs, Read From the RulebooksJudo, sambo and jujitsu: where they differ

From the Kodokan's point of view, Rei, or etiquette, is not decoration in Judo. It is the discipline that keeps partner training from becoming violence. Bowing reminds both students that the other person is someone who helps them learn, not an enemy to be destroyed.

Randori is free practice with resistance, while Kata preserves the formal principles behind the techniques. Together they show that Kodokan Judo is not only a contest system, but a method for studying body mechanics, control, respect, and decision making under pressure.

Kodokan lists Judo techniques in a structured way, including Nage-waza, or throwing techniques, and Katame-waza, or controlling techniques. See Kodokan Names of Judo Techniques for the official technique list.

Judo is not throwing alone. Kodokan sources organize the technique names systematically, with Nage-waza, or throwing techniques, numbering 68, and Katame-waza, or controlling techniques, numbering 32, for a total of 100 core techniques. This detail helps explain what Judo is as a system, rather than only as the familiar image of gripping and throwing on the mat.

Readers who want the technique list from the primary source can see Kodokan Names of Judo Techniques, which sets out the Nage-waza and Katame-waza categories officially.

Which judo techniques are actually trained at IMAC Dojo

The judo syllabus at IMAC Dojo runs from Level 1 to Level 7. Throws begin with Ippon Seoi Nage, O Goshi, and Koshi Guruma, then continue to Harai Goshi, O Uchi Gari, Uchi Mata, Tai Otoshi, De Ashi Barai, Tomoe Nage, and Kata Guruma. Groundwork begins with Kesa Gatame, Yoko Shiho Gatame, Kami Shiho Gatame, and Tate Shiho Gatame, then moves to arm locks such as Ude Hishigi Juji Gatame and strangles such as Hadaka Jime, Okuri Eri Jime, and Kata Ha Jime. Ukemi, which is trained before any of it, has four basic forms: Ushiro-ukemi, Yoko-ukemi, Mae-ukemi, and Mae-mawari-ukemi.

How many belts does Judo have? The grading pathway at IMAC Dojo

The dojo grading pathway runs from white to green, light blue, brown, and black, and each step carries its own technical criteria. White to green is assessed on Rei, Ukemi, Uchikomi, basic throws, groundwork, and Kata-Randori. Green to light blue adds Mae Mawari Ukemi, Harai Goshi, O Uchi Gari, Kata Gatame, and Okuri Eri Jime. Light blue to brown uses competition results or accumulated results against the set standard. Brown with a black tip to 1st Dan requires time held at grade, a minimum age, and an examination covering Tachi-waza, Shime-waza, Kansetsu-waza, Ne-waza, and Nage-no-kata.

The answer is yes, but beginners should start with Ukemi, posture, movement, gripping, and controlled partner practice before heavy Randori. The All Japan Judo Federation beginner resources are useful because they explain Judo as something people can start step by step, not only as a competitive sport.

AJJF also highlights Ukemi for safe falling, which is especially relevant for children, seniors, and adults who want a safer first step into martial arts.

As for the question can Judo help you defend yourself, it helps a great deal at close range, such as being grabbed, pulled, pushed, or knocked off balance, because Judo teaches receiving force, balance, control, and safe falling. It should not be oversold, though: no single art solves every situation. A sound goal is to improve your chances of getting through safely and to leave the situation with a clear head.

The question that follows "what is judo" is usually "how many belts are there", and it has two layers, exactly as karate does. The first layer is the rank system, which is numeric. The second is belt colour, which each organisation sets for itself. Almost all the confusion comes from mixing the two. The same structure is set out in our guide to what karate is.

On the first layer judo uses two words, Kyu and Dan. Anyone below black belt holds a Kyu grade, counting down from a high number to Kyu 1, and Dan grades then count upwards. That structure comes from the Kodokan system and is carried on by judo federations worldwide.

The second layer is the one no single number answers. There is no single worldwide colour standard. The number of steps and the order of colours differ by country and by organisation, so one body's green belt is not automatically another's. Before comparing grades with anyone, ask whose system they were graded in.

So that this rests on something real rather than a floating number, the ladder the judo class at IMAC Dojo grades on runs white, green, light blue, brown, black, and each step carries its own technical criteria. White to green covers Rei, Ukemi, Uchikomi, the basic throws, groundwork, and Kata-Randori. Green to light blue adds Mae Mawari Ukemi, Harai Goshi, O Uchi Gari, Kata Gatame, and Okuri Eri Jime. Brown with a black tip to 1st Dan requires time held at grade, a minimum age, and an examination across Tachi-waza, Shime-waza, Kansetsu-waza, Ne-waza, and Nage-no-kata.

A black belt is not a finish line but the point where training changes mode, and the standards applied differ between a Thai competition and one in Japan, which is compared in our guide to judo competition rules in Japan and Thailand.

Read next · Shinkyokushin KarateWhat Is Karate? How Many Styles, How the Belt Ranks Work, and the Basic TechniquesKarate belts: the same Kyu and Dan, different colours

Students looking for Judo classes in Bangkok can explore the IMAC Judo Academy course page. The program emphasizes fundamentals, safety, Ukemi, etiquette, step-by-step training, and real progress for children, adults, and beginners.

You can also review the IMAC Dojo instructor team and continue reading the IMAC Dojo martial arts blog to choose the training path that fits your goals. For Thailand-specific federation context, see the Judo Association of Thailand.

If your main goal is looking after yourself in daily life, especially as a beginner or a woman who wants to train safely, see the women's self-defense classes page to compare how Wing Chun, Judo, and Karate work together to lay a foundation for self-defense. If competing in Japan is the goal, the rules that differ are set out in judo competition rules in Japan and Thailand.

If you are still deciding whether judo is the right art for you, the overview of the families and how to choose is in what the martial arts are.

Read next: What Is Jujitsu? How It Differs From BJJ and Judo.

Read next: Judo vs Karate: How Do They Differ? Explained From a Real Instructor's Perspective.