Mindfulness and mastery through movement
Weekly classes in Eltham and Kidbrooke for ages 5 to 16. We teach Brazilian jiu jitsu, kickboxing and shurikenjutsu, and we use it all to build confidence, self-control and character. Built on our own mats over twelve years, by a whole generation of students & parents.
Classes are back from Monday 14th September. New ninjas can join any week of term.
Sutcliffe Park · Thomas TallisWe group classes by school year so children train alongside their friends, and so every class stays evenly matched for size, strength and ability. Pick your child's year group and we'll show you every session they can join this term.
Three programmes, one journey. Plenty of our students joined in Year 1 and are now teenagers in Kaizen. Some of them are teaching the next generation.
Playful and non-contact. Cubs build balance, coordination, a strong core and confidence in their bodies through games and challenges. At this age the fun is the learning. Cubs is taking a pause while we find our new permanent home, and it reopens the day we move in.
The heart of what we do. Three age bands, each with its own class: Beginners (Years 1 and 2), Intermediate (Years 3 and 4) and Advanced (Years 5 and 6). Jiu jitsu, kickboxing and shurikenjutsu, eleven belts to earn, and a Two-Week Personal Challenge with every one of them.
Kaizen means continuous improvement. Four sessions a week across BJJ, Muay Thai and kickboxing, plus a competition class for anyone who wants to take it further. From Year 7 students can also join the Junior Instructor Pathway and start learning to teach alongside us.
After Kaizen there's our adult programme and the Adult Instructor pathway. Some of the team teaching today started here as Ninja School students.
Every child in Ninja School trains all four elements every term. Each one is a real discipline with its own syllabus, and each one brings out something different in your child.
Breathing, focus and awareness. Learning to notice, settle, and bring attention back when it drifts. This one runs through everything else we do.
Grappling. Staying calm under pressure, solving problems with a partner, and learning to work with resistance rather than fight it.
Throwing-star training with origami stars folded from paper. Precision, balance and composure. It's the quietest skill in the room and often the hardest.
Striking with pads and partners, plus conditioning. Commitment, effort, and the kind of change that only comes from working hard.
The elements pair up as students grow. Beginners train Air and Fire together, because wind amplifies fire. Intermediates train Water and Earth, grounding emotion as the techniques deepen. By Advanced, all four converge and each student finds their own meaning in them.
No two weeks are the same. The games change, the techniques change, and every age group trains differently. But underneath, a class holds a steady shape:
"There is no wrong or right way to be so I am just going to be me!"
"We use a fun and interactive Ninja Narrative to keep the children engaged and stimulated. Every lesson includes problem solving games to sharpen the mind and challenging exercises to strengthen the body."
Harry Bovill · Founder
At its core, Ninja School is a developmental programme for children. Martial arts is the vehicle, and we chose it because nothing else asks so much of a young person in such an honest way. What we're really building is the whole child.
At Ninja School we integrate mind, body and heart practices:
Children here learn real martial arts. The jiu jitsu follows a full syllabus, techniques are taught step by step, and every grade is earned on the mat.
The mat gives honest feedback. We hold high standards inside a warm, safe room, so children learn that effort and enjoyment go together.
Stripes recognise skills, but they don't finish a belt on their own. Once the stripes are earned, parents set a Two-Week Personal Challenge at home, and the belt is awarded when it's done. Stripes complete the requirements. The challenge completes the belt.
Around a quarter of our students have SEND, and 99% of families told us the programme is inclusive. Every child gets the same structure, the same expectations and the same care.
Every class is led by a DBS-checked adult instructor. Junior instructors assist under supervision and are never left in charge. The last 15 minutes of every class is open for parents to come in and watch.
Nothing on this page came off a shelf. The syllabus, the games and every one of the eleven belts were tested, broken and reshaped by the children who trained here, year after year. Families stay, siblings follow, and the first generation now helps teach the next.
"At Ninja School we integrate mind, body and heart practices. It's the kind of education very few of us got from mainstream schooling, and exactly the kind that is essential today. Through the discipline of martial arts training, and through the principles and mindfulness philosophies of Ninja School, we help kids develop themselves holistically. We give them a safe space to be aware and develop; a space to move and a space to express.
We do this so they can build healthier relationships, so they can be more in tune with their bodies, and so they have the mental fortitude to let go of fears and listen to their intuitive wisdom. In this way we prepare the next generation for a more empathetic, compassionate and conscious world."
Harry Bovill · Founder
Ninja School was built and nurtured by three of us, together, over twelve years. Everything on this page has all three of our fingerprints on it.
Social entrepreneur and the visionary behind Ninja School. What Harry is proudest of is not building it alone, but drawing on his co-founders, students and parents to turn big ideas into something tangible: the Four Element curriculum, the belt system and the pedagogy underneath it all. Today he leads the teens, the camps and the residencies.
Historian by degree, athlete by lifelong habit, and a dedicated jiu jitsu practitioner. Jon has shaped Ninja School since the start, and today he leads the school itself: the weekly classes, the students and the standards they're held to.
Movement coach, qualified PT and boxing coach. Reece has always held that the movement-aware child is the future, and Ninja School is that belief made real: his thinking runs through the games, the warm-ups and the conditioning of every class.
"We create an environment where children don't just strive to improve themselves, but to help those around them improve."
The Ninja Way
Every belt has a green tag at the end where the four element stripes are awarded, plus a personal challenge to finish it. Children grade in class, in front of their friends. No exam-day nerves, just steady progress they can see.
Four full stripes per belt, one per element, earned in any order.
Eight half stripes per belt. Each element stripe is earned in two halves as the work deepens.
Four Air stripes per belt, one at a time. Mushin is earned by teaching alongside the team.
Stripes are awarded in class when a skill is shown reliably. Children always know what the next stripe asks of them, so the next step is never out of reach.
The Two-Week Personal Challenge completes each Ninja School belt, and it belongs to you, not us. When the stripes are done, you set a two-week challenge for your child at home, you watch them earn it, and only when you confirm it is the belt awarded. Stripes complete the requirements. The challenge completes the belt.
After Mushin, Kaizen students move through three black belts, each carrying a colour of the journey so far. The final award is the full adult blue belt in Brazilian jiu jitsu, from age 16 at the earliest. It marks the end of the childhood journey and the start of the adult one.
Kaizen grading works a little differently. Four stripes are earned through attendance and progress, and there's no personal challenge at this stage. Instead, students enter an eligibility zone, where in effect they earn "one more stripe" before the next belt is awarded, and what that takes is different for every student. Training regularly and coming to camps, most can expect one to two stripes a term.
Students who join Kaizen without coming through Ninja School earn their way to Mushin first: White, then Grey White, then Grey, then Mushin, with four full white stripes needed on each belt.
"Ninja School is an integral part of our weekly routine and a critical part of our children's development."
Parent, 2025 community consultation
"Ninja School provides a safe and inclusive space where children can feel supported and fulfil their potential."
Parent, 2025 community consultation
Weekday classes in Eltham, evenings and weekends in Kidbrooke. Families come to us from Blackheath, Lee, Lewisham, Hither Green, Greenwich, Charlton and right across South East London, and both venues are minutes from the A2. Drop off at the start, and come back for the last 15 minutes to watch.
| Mon, Tue & Thu | 16:15–17:30 | Ninja School · Years 1–3 |
| Mon, Tue & Thu | 17:45–19:00 | Ninja School · Years 4–6 |
| Cubs | paused | Reopens at our new permanent home · join the waiting list |
| Monday | 18:15–19:30 | Kaizen · Muay Thai / Kickboxing |
| Thursday | 18:15–19:30 | Kaizen · BJJ |
| Saturday | 09:30–10:45 | Ninja School · Years 1–4 |
| Saturday | 11:00–12:15 | Ninja School · Years 5–6 |
| Saturday | 11:00–12:15 | Kaizen · BJJ |
| Saturday | 12:30–13:45 | Ninja School · Years 1–4 |
| Sunday | 12:30–13:45 | Ninja School · Years 1–4 |
| Sunday | 14:00–15:15 | Competition class · open to all Ninja School & Kaizen |
| Sunday | 15:30–16:45 | Ninja School · Years 1–2 |
One fee per term covers your child's weekly class, grading, stripes and belts. Autumn term starts Monday 14th September.
Your first class is free. Siblings get 10% off. Fees are taken at the start of each term.
Comfy sports clothes and bare feet on the mat. Once they join we'll sort them out with a Ninja School gi and white belt.
Contact is introduced gradually, always with rules, supervision and a partner of a similar size. Cubs are non-contact. Bumps happen like in any sport, but injuries are rare and every class is run by trained, DBS-checked instructors.
Very likely, yes. About a quarter of our students have SEND, and the structure and clear expectations suit a lot of children who find other settings hard. Tell us what helps when you book and we'll plan the first session with you.
We ask parents to head off after drop-off and come back for the last 15 minutes, which is always open for you to watch. There's an honest reason: children focus better, try harder and take braver decisions without an audience, and walking into the room on their own is one of the first independence skills we build. For our youngest ninjas, or any child finding the start hard, we'll take it gently while they settle in.
Yes. Ninja Camp runs in the school holidays and we do a surf residency every May. Current students hear first, so email us if you'd like to be on the list.
Yes. Our adult programme trains at Thomas Tallis on Monday and Thursday evenings and Sunday afternoons. Email us for details.
Tell us a bit about your child and we'll get straight back to you with a class to try, usually the same week.
