Martial Arts (Karate, Kendo, Judo): What Starting in Early Childhood Means, and the Pitfalls

Why this topic is on your mind

Around age 5, you hear more and more that friends in the nenchū and nenchō classes have started karate, kendo, or judo. Children going to the dojo in hakama, greeting people in loud voices, bowing on the tatami mats: it is natural to be moved by this dignified bearing, not seen at ordinary daycare or kindergarten, and to think “I’d like that for my child too”.

In this situation, questions like these come up at home.

• Is it true that martial arts teach children manners?
• I often hear that it “makes children mentally strong”, but is there any basis for that?
• Karate, kendo, judo: which suits a 5-year-old?
• I’m worried about injuries. I’ve heard that in judo especially, children hit their heads. Is it safe?
• In the first place, is age 5 too early to start? Or is it already too late?

Developmental psychology, sports medicine, and the guidelines of each martial arts federation give fairly well-organized answers to these. It is not as simple as “doing martial arts develops the mind”, nor is it “too late if you don’t start at 5”. On the other hand, there certainly are elements that can develop when traditional teaching methods and continuity come together, and it is worth choosing after understanding the features of each discipline and the safety risks. Let’s look at them in turn.

Elements common to martial arts: what is different from sports?

What decisively sets martial arts apart from soccer or gymnastics is that they are structured so that “technique” and “etiquette” cannot be separated. Japanese martial arts, whose educational value was redefined from the Meiji era onward and which were built into school and community physical education after the war, have positioned the following four as common pillars.

• Rei (etiquette): bowing at the beginning and end of practice, respect for one’s partner, respect for the dojo. The guidelines of each federation agree that “beginning with a bow and ending with a bow” means more than a formality.
• Posture (physical and mental readiness): a posture with the back straight, the center of gravity low, and squarely facing one’s partner. This is a bodily technique and at the same time an expression of a mental “stance”.
• Respecting one’s partner: although these are person-to-person disciplines, the partner is seen not as an “enemy” but as “someone you practice with”. Exchanging bows even after a match reflects this idea.
• Knowing one’s own body: developing body awareness through practice that pays attention to the position of one’s hands and feet, center of gravity, and breathing. This also overlaps with the developmental tasks of early childhood.

Vertonghen and Theeboom (2010)A review paper summarizing the psychosocial effects of martial arts practice among youth integrates martial arts research from countries around the world and concludes that “with traditional martial arts teaching (a style that emphasizes etiquette and philosophical elements), improvements in self-regulation, self-esteem, and sociability are reported, while with teaching that emphasizes only winning competitions, increases in aggression and decreases in prosocial behavior are sometimes reported”. In other words, the key point of the research is that the psychosocial effects of martial arts are determined not by “being martial arts” but by “how they are taught”.

What does the research say?

On martial arts in early childhood, findings have accumulated from four angles: (1) studies of effects on self-regulation, (2) reviews of psychosocial effects, (3) studies of the risks of early specialization, and (4) injury risk statistics. Let’s answer the questions mothers of 5-year-olds worry about with each body of research.

Question 1: Is it true that children “become mentally strong” and “learn manners”?

This is probably the effect most families hope for. Let’s look at how the research sums it up.

Lakes and Hoyt (2004)A randomized controlled study examining the effect of school-based traditional martial arts training on children’s self-regulation randomly assigned about 200 children aged 5 to 11 to a traditional Korean martial arts program (a traditional style related to taekwondo) or a regular physical education program, and compared cognitive, affective, and physical self-regulation after 3 months. It reports that the martial arts group showed significantly higher scores on a cognitive self-regulation test, teacher-rated behavioral self-regulation, and performance on motor tasks (p<0.05). An interesting finding is that the effect was especially large in boys.

What we want to note, however, is that the intervention in this study was “traditional teaching that emphasized etiquette, breathing, bodily technique, and philosophical values”. The implication of the paper is that it is not that “any martial art develops self-regulation”; “traditional teaching methods that emphasize etiquette and self-reflection” are the key. Even in taekwondo, similar effects have not been confirmed for styles that emphasize only winning competitions.

the review by Vertonghen and Theeboom (2010)A narrative review summarizing 27 studies from countries around the world on the psychosocial effects of youth martial arts reaches a summary in the same direction. It concludes that “the psychosocial effects of martial arts differ greatly by discipline, teaching style, duration of practice, and quality of instructors, and it cannot be said uniformly that ‘martial arts develop the mind’”. Specifically, it summarizes a tendency for positive effects to be reported with traditional teaching (emphasizing etiquette, forms, and philosophy), and neutral or partly negative effects with competition-oriented teaching (emphasizing winning).

Therefore, “learning manners” and “becoming mentally strong” are effects that can develop when “traditional teaching × continuing × fit with the child” all come together, not something acquired automatically by attending martial arts classes. The research summary is that if you leave it all to the dojo, thinking “it’s martial arts, so it’s fine”, without looking at the dojo’s teaching policy, the effects you hoped for are hard to obtain.

Question 2: Is age 5 too early to start? What do each organization’s guidelines say?

Each martial arts federation has age-based coaching guidelines. Here are the key points.

the All Japan Judo Federation youth judo guidelines (2020)Official guidelines on step-by-step coaching of youth judo and accident prevention state that when starting before school (nenchū or nenchō), it should be kept at the stage of “developing a feel for breakfalls through play”, and full coaching of throwing and groundwork techniques is preferably from the lower grades of elementary school onward. The rank (dan) certification exam for youth is set from age 9 (first dan from age 13), so a 5-year-old is not at the stage of aiming for “promotion”.

the All Japan Kendo Federation coaching guidelines (2019)The AJKF’s official guidelines on coaching youth kendo state that “from the standpoint of physical development and concentration, around the time of entering elementary school is one rough guide for learning kendo forms and basic movements”. At earlier ages, “kids’ kendo” and “children’s kendo classes” that start step by step with how to hold the shinai (bamboo sword), basic swings, and etiquette are common. Kyu-grade certification is set from the lower grades of elementary school, and the first-dan examination from age 13 and up.

the Japan Karatedo Federation youth division guidelines (2021)Competition rules and coaching guidelines for the youth division state that “from the standpoint of physical development and safety management, kumite (attack and defense against a partner) is in principle from entry to elementary school onward”. In preschool classes (ages 4 to 6), the usual teaching centers on basic punches and kicks, kata (forms), and etiquette, without kumite against a partner. Kyu-grade certification exams differ by dojo and school of karate, but many have a step-by-step kyu-grade system starting from around age 6.

In other words, none of the organizations rejects starting at age 5 itself, but “step-by-step coaching suited to age” is a premise. Rather than being at the stage of demanding competition or promotion from a 5-year-old, the appropriate position, both in research and for each organization, is “experiencing etiquette, basic movements, breakfalls (judo), basic swings (kendo), and kata (karate) as an extension of play”.

Question 3: What happens if you put a young child through hard martial arts training?

Brenner et al. of the American Academy of Pediatrics (AAP) (2016)A 2016 clinical report on early sports specialization and intensive training in young athletes states, for person-to-person competitive sports including martial arts, that “until around age 12, participating in several sports reduces the risk of injury, stress, and burnout”. Multiple studies agree that “early specialization” training, in which a child is made to throw themselves into one martial art 4 to 5 times a week from early childhood, is associated with overuse injuries, burnout, and dropping out of sport.

Martial arts are disciplines with a distinctive two-sided nature: some families pursue them with a competitive orientation, while many others continue them as “lifelong learning of etiquette and bodily technique”. At age 5, “making a child train hard with the aim of developing a future competitor” is not the path ordinary families take. Starting with youth classes of about 1 hour once or twice a week, putting your child’s enjoyment first, is a manageable line both in terms of research and each organization’s coaching guidelines.

Question 4: The risk of injury, especially head injury in judo

This is an important issue that families should be told honestly.

the Consumer Affairs Agency Consumer Safety Investigation Commission report on judo accidents (2017)An advisory on judo accidents at school, especially the risk of head injury states that judo is a discipline with a higher incidence of head injury (such as acute subdural hematoma) than other sports, and that “beginners”, “cases where the child was thrown and could not do a breakfall”, and “insufficient supervision by instructors” are repeatedly pointed out as factors in serious accidents. Many of the fatal accidents and cases of severe lasting disability in school judo resulted from the head hitting the tatami hard.

In youth judo classes in early childhood (around age 5), it is common to stay at the stage of “repeatedly practicing breakfalls as an extension of play”, without full throwing matches, so the risk of the kind of serious accidents the Consumer Affairs Agency points out is much lower. However, the Consumer Affairs Agency’s advisory clearly calls for families, when choosing a dojo, to always check “how carefully breakfalls are taught”, “whether randori (free sparring) is introduced step by step according to age”, and “the arrangements for responding to accidents (links with medical care, insurance)”.

Karate and kendo are not injury-free either. In karate kumite there is a risk of bruising to the face and abdomen, and in kendo there are risks such as bruising from the shinai, blisters on the feet, and heat illness (the inside of the protective gear tends to get very hot). However, in terms of the risk of serious head injury, current statistics show judo is higher than other martial arts. It cannot be said that “it is dangerous, so you should avoid it”, but the research summary is that an attitude of “choosing a dojo while knowing the risks” is necessary.

Features of each discipline: karate, kendo, judo, and how they differ for a 5-year-old

To think about the order and fit for 5-year-olds, here are the structural differences among the three disciplines.

As a rough guide for choosing, please take the editorial team’s summary as one reference.

• Children who like to concentrate alone, or for whom their own pace matters: a traditional (stopping just short of contact) karate dojo tends to suit them relatively well. Much of the practice involves polishing kata, and kumite against a partner is introduced step by step.
• Children who like using a loud voice, or who admire a dignified posture: kendo sometimes suits them. Practice of shouts (kiai) and posture gives children an easy-to-see sense of achievement.
• Children who don’t mind physical contact, or who love active physical play: judo is a discipline with a strong affinity with play. But always check the quality of the dojo’s breakfall teaching.
• Cautious children, or children sensitive to pain: at age 5, start with a karate preschool class or a kendo class centered on basic swings, and introduce kumite and matches step by step while checking the child’s own wishes.

In the end, the most reliable way to judge “fit” is to watch your child at a trial session.

A guide to the age to start: summary of each organization’s guidelines

Setting out each martial arts organization’s age-based guidelines as a timeline gives the following.

1. Ages 4-5

   'Martial arts play' stage

   Centers on etiquette (greetings, seated bow, standing bow), basic posture, and body movement as an extension of play. Each organization recommends 'enjoyment first, with formal technical instruction kept to a minimum'. In judo, breakfalls through play; in karate, basic movements through play; in kendo, starting by imitating swings.

2. Ages 6-7 (around school entry)

   Starting full acquisition of basic movements

   The AJKF states that full learning of kendo forms and basic movements is 'around the time of entering elementary school'. The karate federation states that 'kumite is in principle from entry to elementary school onward'. Judo introduces the basics of throwing techniques step by step (though match-style practice gets fully under way only in higher grades).

3. Ages 8-9

   Dan and kyu examinations get fully under way

   AJJF youth dan promotion is from age 9 (kyu grades from before that). In karate and kendo, kyu-grade examinations also get fully under way at each dojo. This is when children themselves start to feel motivated, saying 'I want to get better' or 'I want the next belt', and it is the point where competitive and hobby orientations diverge.

4. Ages 10-12

   Competing and thinking about future paths

   Participation in district tournaments and federation-run tournaments increases. The AAP (2016) states that 'multiple sports in parallel are preferable until age 12', so this is the time for the family to discuss whether to focus on martial arts. Both continuing as a hobby and throwing oneself into competition are possible.

5. Age 13 and up

   First-dan examination / competitor development stage

   The AJJF and AJKF first-dan examinations can be taken from age 13 and up (the exact age differs slightly by organization). If the child has the will and interest to continue, this is when the foundation for continuing as 'lifelong martial arts' becomes solid. Since these are not disciplines that require early specialization, there is no need to rush to narrow down future paths.

What this timeline shows is that these are not disciplines where “you won’t make it unless you start at 5”. Full acquisition of technique and dan promotion come from the school years onward, and whether to start martial arts at age 5 is reasonably judged, both in research and by each organization, not “for the future” but by “whether the child can enjoy it now”.

What to do if you actually go ahead

Based on the research and each organization’s guidelines, here are decision criteria that are easy for families to use.

1. Checkpoints for choosing a dojo: check the instructors’ qualifications and policy

Here are the points we would like you to check before going to a trial session.

• Instructors’ dan certification and coaching qualifications: whether they hold the coaching qualifications and dan certificates issued by each federation. You can check on the federation’s official website whether the dojo is registered. This is a point that distinguishes it from a “so-called ○○ dojo” that only has a sign.
• How etiquette is handled: whether careful bows are made at the beginning and end of practice, and whether the meaning, not just the form, is conveyed to the children. A dojo where “beginning with a bow and ending with a bow” has not become an empty formality is an indicator that traditional teaching methods are working.
• Arrangements for dealing with injuries: emergency arrangements, links with medical care, enrollment in sports safety insurance, and transparency about how past accidents were handled. In judo in particular, following the Consumer Affairs Agency’s advisory, more dojos in recent years publish their accident prevention efforts.
• How children’s autonomy is handled: whether they avoid forcing a child who says “I don’t want to”, whether they avoid stirring up nothing but winning and losing, and whether they coach step by step according to age. As Vertonghen & Theeboom point out, win-at-all-costs teaching can have negative psychosocial effects.
• Class size and instructor ratio: in preschool classes, once there are more than 10 children per instructor, the quality of safety and teaching tends to fall.

2. Choose the discipline by “your child’s face at the trial session”

Information in advance matters, but the final decision depends most on how your child is at the trial session.

• Does your child say on their own afterwards, “I want to go again”?
• Is your child frightened by the atmosphere of the dojo (the instructors’ voices, how the other children are)?
• During etiquette, does your child show interest while being nervous?
• On the way home, does your child talk about practice on their own, or fall silent?

If you keep making a 5-year-old attend “for the future” against their wishes, they may come to dislike martial arts and be less likely to take them up again after adolescence. Putting “whether your child enjoys it” first is the foundation for building a good long-term relationship with martial arts.

3. Monthly fees, equipment, continuity: put realistic costs on the table

• Monthly fees: typically karate ¥5,000-10,000, kendo ¥5,000-8,000, judo ¥3,000-6,000 (large differences by area and dojo). Judo can often be started cheaply at local federation-affiliated dojos.
• Equipment: karate needs only a uniform (from a few thousand yen), judo a judo uniform (a few thousand yen to ¥20,000), and kendo at first only a shinai and uniform (a few thousand yen), but at the stage when a full set of protective gear is needed, there is an expense of ¥30,000-100,000. For kendo, it is reassuring to budget for medium- to long-term costs.
• Taking your child there and back: martial arts often have practice in the late afternoon or evening. A dojo within walking or cycling distance is an indicator that it will be easier to continue.
• Make-up classes and leave of absence: checking at the start the make-up system for when your child misses practice because of fever or events, and how long-term leave is handled, makes it easier to continue without strain.

4. Involvement at home: supporting your child’s autonomy

A guide to how families can be involved as children continue with martial arts.

• When your child wants to talk about practice, listen calmly: rather than grilling them with “What technique did you do today?”, be ready to listen when your child wants to talk.
• Don’t force review at home: only a minority of 5-year-olds practice swings or kata on their own at home. Forcing them with “Do it at home too” makes them dislike practice itself.
• Look at the process rather than kyu or dan results: talk mainly about “How was practice today?” rather than “What’s your next grade?”. The AAP also recommends “involvement that values the process over results”.
• When your child says “I want to quit”, don’t immediately ask them to take it back: listen calmly to the reasons, and take time to judge whether it really doesn’t suit them or whether it is a passing mood. Long-term leave is also an option.

5. Run “manners” alongside at home too

Simply “outsourcing” manners to a martial arts dojo has limited effect, according to the research as well. Having “itadakimasu” (said before meals), “gochisōsama” (said after meals), “thank you”, and “sorry” rooted in daily life at home is the foundation that supports learning etiquette at the dojo. Whether or not your child attends martial arts, it is worth keeping in mind that etiquette is basically built up day by day at home.

Closing dialogue

Research details

Primary sources

Lakes & Hoyt2004Journal of Applied Developmental Psychology, 25(3), 283-302

Study design: School-based randomized controlled trial (RCT)

Participants: About 200 children aged 5 to 11 at one US elementary school, randomly assigned to a traditional Korean martial arts program group (related to taekwondo, traditional teaching style) or a regular physical education program group, with a 3-month intervention

Main results: • The martial arts group showed significantly higher scores than the control group on a cognitive self-regulation test, teacher-rated behavioral self-regulation, and motor task performance (p<0.05) • The effect was especially marked in boys • The intervention program used a traditional teaching style emphasizing “etiquette, breathing, forms, self-reflection, and philosophical values”, not one emphasizing winning competitions • It showed not that “any martial art is effective” but that “martial arts programs using traditional teaching methods” may develop self-regulation

Limitations: A study at a single school, so care is needed in generalizing culturally and regionally. The intervention period was a medium-term 3 months, and long-term effects need separate verification. The quality of the instructor (a well-known traditional instructor) may affect reproducibility.

Vertonghen & Theeboom2010Journal of Sports Science and Medicine, 9(4), 528-537

Study design: Narrative review of the psychosocial effects of youth martial arts practice (integrating 27 studies)

Scope: Research on the psychosocial effects of various martial arts (karate, judo, taekwondo, kung fu, aikido, etc.) among youth in countries around the world (US, Europe, Asia)

Main results: • The psychosocial effects of martial arts differ greatly by “teaching style”, “duration of practice”, and “quality of instructors” rather than by “discipline” • With traditional teaching (emphasizing etiquette, forms, and philosophical elements), there is a tendency for improvements in self-regulation, self-esteem, and sociability to be reported • With teaching that emphasizes only winning competitions, increases in aggression and decreases in prosocial behavior are sometimes reported • It cannot be said uniformly that “martial arts develop the mind”, and an understanding of the teaching context is essential

Limitations: A narrative review that does not quantitatively integrate effect sizes as a meta-analysis would. The quality and design of the included studies vary, so care is needed in causal inference.

StrongBrenner & AAP Council on Sports Medicine and Fitness2016Pediatrics, 138(3), e20162148

Study design: Clinical report of the American Academy of Pediatrics (recommendations of an expert panel based on a systematic review)

Scope: Early sports specialization and intensive training in young athletes (from preschool to adolescence)

Main results: • Until around age 12, participating in several sports reduces the risk of injury, stress, and burnout • In many sports, delaying specialization until late adolescence (around ages 15-16) gives a higher chance of achieving long-term competitive goals • Specializing in a single sport from early childhood is associated with overuse injuries, psychological stress, and dropping out of sport • The same applies to person-to-person competitive sports, including martial arts

Limitations: A policy statement; recommendations by an expert panel rather than new research. The optimal time to start specializing differs by sport. Cultural and regional differences need further verification.

All Japan Judo Federation2020全日本柔道連盟 公式指導指針 [All Japan Judo Federation official coaching guidelines]

Study design: Official guidelines for coaching youth judo by the sports federation (compiled by an expert committee)

Scope: Youth judo in Japan (preschool to junior high school)

Main results: • When starting before school (nenchū or nenchō), it should be kept at the stage of developing a feel for breakfalls through play, and full coaching of throwing and groundwork techniques is preferably from the lower grades of elementary school onward • The youth dan certification exam is from age 9, and the first-dan examination from age 13 • For accident prevention, recommends as essential items thorough breakfall teaching, step-by-step introduction of randori according to age, and links with medical care and insurance • In principle, instructors hold a coaching qualification certified by the federation

Limitations: A guideline, not an empirical study. How thoroughly it is applied differs from dojo to dojo locally.

All Japan Kendo Federation2019全日本剣道連盟 指導要領 [All Japan Kendo Federation coaching guidelines]

Study design: Official guidelines for coaching youth kendo by the sports federation

Scope: Youth kendo in Japan (preschool to junior high school)

Main results: • Around the time of entering elementary school is one rough guide for full learning of kendo forms and basic movements • Before school age, children start step by step with how to hold the shinai, basic swings, footwork, and etiquette • Kyu-grade certification is from the lower grades of elementary school, and the first-dan examination from age 13 and up • Wearing protective gear is generally from entry to elementary school onward, from the standpoint of physical development and safety management • Asks instructors to take measures against heat inside the protective gear in summer, ensure hydration, and provide appropriate breaks

Limitations: A guideline; the age categories are rough guides. Flexible application according to each child’s individual development is a premise.

Japan Karatedo Federation2021全日本空手道連盟 競技規定および指導指針 [Japan Karatedo Federation competition rules and coaching guidelines]

Study design: Official guidelines for coaching youth karate by the sports federation

Scope: Youth karate in Japan (preschool to junior high school), traditional lineage

Main results: • Kumite (attack and defense against a partner) is in principle from entry to elementary school onward, from the standpoint of physical development and safety management • In preschool classes (ages 4 to 6), the usual teaching centers on basics (punches and kicks), kata (forms), and etiquette, without kumite against a partner • Kyu-grade certification exams differ by dojo and school of karate, but many have a step-by-step system starting from around age 6 • Teaching policies differ greatly between stopping just short of contact (traditional) and full contact, so this needs to be checked when joining

Limitations: The Japan Karatedo Federation is an organization centered on the traditional lineage; full-contact organizations are separate. Note that teaching differs greatly by school of karate and dojo.

Consumer Affairs Agency, Consumer Safety Investigation Commission2017消費者庁 事故調査報告 [Consumer Affairs Agency accident investigation report]

Study design: A review of accident statistics and an advisory by the national government (Consumer Affairs Agency) (centered on school judo accidents)

Scope: Cases of serious accidents in school judo in Japan (mainly junior high and high school)

Main results: • Judo is a discipline with a higher incidence of head injury (such as acute subdural hematoma) than other sports • Many of the fatal accidents and cases of severe lasting disability in school judo resulted from the head hitting the tatami hard • “Beginners”, “cases where the child was thrown and could not do a breakfall”, and “insufficient supervision by instructors” are repeatedly pointed out as factors in serious accidents • For accident prevention, strongly recommends thorough breakfall teaching, step-by-step coaching for beginners, and putting in place arrangements for links with medical care

Limitations: The data are mainly from school judo (junior high and high school), and statistics for preschool classes need to be checked separately. Comprehensive data on accident statistics at local dojos are limited.