The best martial art for any child:
There are many types of martial arts practiced, but the most widely available - and most suited to children - include:
1 Karate. Literally meaning 'empty hand', Karate is one of the most traditional martial arts. ...
2 Judo. ...
3 Taekwon-Do. ...
4 Aikido. ...
5 Kung Fu. ...
6 Jiu Jitsu. ...
7 Tang Soo Do.

Best martial arts for 4,5,and 6 year old children
Should Your Kid Take Karate or Judo or taikowndo? Here's the Difference Between 5 Martial Arts

Tae Kwon Do. Country of origin: Korea.
Tae-kwon-do had a huge impact on my boy, from his daily encounters with aggressive kids at school, to his daily play with his mates. He is more assertive now, than ever, and stands his ground, firmly. I would hate to wreck that with the wrong decision

Aikido is the Best Martial Arts for Little Girls
aikido might be nice for a little girl as the dojos tend to be friendly and unintimidating. she will also get to roll around on the floor, which kids almost invariably love.
however, I am not sure it meets your criteria for strong self defense skills. there is a aikido dojo on smith street in brooklyn that has a very good reputation.

Karate. Country of origin: Japan.
Martial arts are great for kids. They offer exercise, discipline and camaraderie. ... Martial arts, such as judo, kung fu, kick boxing and taekwondo, teach many valuable skills — discipline, self defense, balance, strength and flexibility.
Is Karate for children?
Karate is good for ADHD
Most experts recommend that children use karate to complement, not replace, their ADHD medications.
He also stresses that while exercise in general is good for children with ADHD, martial arts offers more benefits than many other forms of exercise, such as soccer or baseball.

karate or taekwondo better?
There are some throws and joint locks taught in karate, but they are not the focus of the style.
The majority of karate practitioners learn a more balanced approach to kicking and hand strikes than taekwondo practitioners do, as taekwondo relies more on kicks.
In that sense, it is similar to taekwondo.


Kung Fu. Country of origin: China.

1. Kids with a martial arts background, however, are continually reminded of how essential self-discipline is.
2. Partner-driven forms like jiu jitsu can also foster camaraderie, as they force kids to pair off and build their skills together.
3. Enrolling an inactive child in such a physically demanding pastime not only discourages the sedentary lifestyle she’s used to, but also gives her an enjoyable activity that inspires her to keep moving.
4. When your child strives toward each new belt, he’s learning valuable lessons about setting and reaching his goals.
5. Kids who struggle with a low sense of self-worth usually become more confident as time progresses while they’re enrolled in a martial arts class.
6.  though, your child will be learning lessons in respect along with new moves.
7. many defensive styles teach kids peaceful, non-violent conflict resolution skills and emphasize the importance of avoiding a physical altercation.
8. Kids who aren’t always adept when it comes to paying attention to what they’re told can benefit from the verbal instruction and one-on-one work in her dojo.
9. Working together to learn new things and accomplish goals is an important life lesson for kids to learn
10. affect his behavior at home and have an all-around good influence on him as he develops into an adult.

Jujitsu, from Brasil 
One of the most important skills learned in Brazilian Jiu-Jitsu is the ability for the child to defend themselves.

Unlike other styles of martial arts, this form doesn't teach unrealistic or “flashy” moves. The Jiu-Jitsu self-defense skills are specially relevant to help children deal with bullying.

Generally, and even more so in this age, it is all about the trainer, not the art. Look for a trainer that has experience with hyperactivity and this age (I, for example, do) and therefore knows how to handle them.

In addition, the layout and methodology of the training can differ a lot within one art, again depending on the trainer.
Top 10 Martial Arts Weapons

There is nothing that prevents you from going around, speaking to people and trying something out. Apart from that, I take this question to be opinion-based, that's why this is a comment, not an answer.

Activities like tae kwon do, kung fu and aikido are a fun way for both boys and girls to achieve fitness and focus.
Some parents may think they also promote violence, but that's a myth, according to experts. The martial arts actually help teach self-discipline and socialization skills.