About  us

Our Vision For You

The Kokoro Aikido Dojo opened its doors in January 2013 under the direction of Karl Ruben. Since then, we have been committed to the vision of strengthening the joy of movement through martial arts. We firmly believe that through Aikido, with its peaceful worldview, we are contributing to a better world. The social nature of our art plays a major role: with us you will find a home in a friendly environment where we support and help each other.

Aikido Stunde

Why Kokoro


Kokoro is the Japanese word for "heart". In Japanese, this also means the right mental attitude. We want to use our name to express what is already obvious in our daily practice: Aikido goes from heart to heart. With dedication, passion and full commitment, you too will leave the mat with a tired smile and a relaxed mind. The desire to be stronger than everyone else has no meaning for us. For us, giving your best in every training is the heart of martial arts - that is Kokoro.

Who We Are

Karl Ruben


Karl Ruben (5. Dan Aikikai)


I came to Aikido at the age of 13. Even as a teenager I was fascinated by this martial art and its philosophy. Since then, in over 20 years of practice, I have continued my studies in every corner of Europe, for a year in the USA and on several visits to Japan.


At the beginning of 2013 I founded the Kokoro Aikido Dojo Berlin. I now teach here several times a week to pass on my experiences and enthusiasm. In 2023 I was awarded 5th Dan for this.


The joy of seeing my students - whether adults or children - come off the mat with drops of sweat on their foreheads and a smile on their faces is indescribable. I am very grateful to be able to share my enthusiasm with other people and support them in their personal growth.

Franziska Dieterich


Franziska Dieterich (3. Dan Aikikai)


I have been practicing Aikido with great joy since 2002. My beginnings on the mat were in the ZfHB with Jochen Knau. I was later influenced by Jorma Lyly and Jan Nevelius (Vanadis Dojo / Stockholm), who are still important teachers for me today.

Because of these influences, I was briefly with Clemens Ziesenitz in Berlin before I found my Aikido home in the Kokoro Aikido Dojo with Karl Ruben in 2013.

For over 10 years I have been following Endo Seishiro Sensei, whose Aikido has had the strongest influence on me. His encouragement to always keep my mind awake and open has opened doors to growth and self-knowledge in Aikido for me.

Regular Aikido practice has kept me on track in many challenges. Therefore, I am grateful that I can make available to others what has brought me joy, clarity, stability, courage, Ki and global connections. Let's go!

Jan Kurfürst


Jan Kurfürst (2. Dan Aikikai)


At the age of 11, my Aikido journey began in Dresden, where training for children and young people sparked my passion for a sporting approach without competition and ego.

In 2018 I moved to Berlin and found my way directly to Kokoro Aikido. Karl and the entire dojo gave me a warm welcome, which helped me gain a foothold in Berlin. Under the direction of Jan Nevelius and Jorma Lyly, I took the 1st Dan exam in Sweden. The 2nd Dan exam followed there in the summer of 2022.

For me, Aikido is the perfect balance to everyday life. In the dojo I find complete mental relaxation in contact with different partners, and the variety of contacts is fascinating.

Resolving conflicts non-violently, without fear of confrontation, keeping one's own center, getting in touch, allowing softness and opening up - these qualities shape not only the dojo, but also my everyday life. For several years I have had the privilege of passing on these qualities as a teacher at Kokoro Aikido. I am very grateful for this trust and look forward to getting to know you on the mat!

Hannah Sauer


Hannah Sauer (1. Kyu)


My Aikido journey began in 2015 at the age of twelve. Since then, this martial art has not only influenced my life, but also guided my personal development. Aikido helped me focus energy, build self-confidence and strengthen relationships.

My teacher Karl played a key role in this. I consider myself lucky to be a member of the Kokoro Aikido Dojo, where the heart lies not only in Aikido itself, but also in the community.


In the dojo I have the privilege of not only improving my own Aikido skills, but also passing on my experiences. I enjoy working with young people and not only offering them an entertaining lesson, but hopefully also having a positive impact on their lives through Aikido, as was the case with me. My goal is to provide children with a safe space to learn new things and make connections. That's why I'm always looking forward to meeting new people on the mat.

Our Principles

The Kokoro Aikido Dojo is a community that offers everyone the opportunity to learn martial arts. We support each other and stand up for...

... an Aikido for true heroes

For us, Aikido is not a matter of age, talent or mere muscle strength. What counts is dedication and commitment. Anyone can bring this with them if they honestly decide to do so. Resting on your skills is boring. True heroism consists in continually pushing one's own boundaries and not accepting standstill.

... the right to ask questions

Questions are an important part of the learning process and with us everyone has the right to ask them and receive a respectful answer. We believe that the Aikido teacher is more than just a trainer. That's why it's okay to approach him at any time with wishes, concerns or questions about martial arts (as long as it's not four in the morning).

… respect on the mat

Everyone has the right to learn in an atmosphere of mutual respect, without being treated in a way that could be perceived as unpleasant. We are all part of a community where respect, integrity, courtesy and fairness are values that we never want to lose sight of.

... good contact with your partner

In Aikido, everyone should be able to expect their training partners to appear hygienic and clean on the mat, to follow etiquette, to help each other, and to never be touched disrespectfully. Of course, that goes double for us. That's why we lead by example and make our mothers proud of us.

… an Aikido without fear

We always want to train in such a way that both partners can grow from the exercise. That's why we trust in Aikido without pain, where safety and safe practice are always guaranteed.

… aspiration and modesty

The classes here are of high quality because we set high standards for ourselves. We enjoy it because each of us makes an effort to keep it that way. And we remain humble because we recognize what kind of work that is.


We believe in laughter, sweat, movement and togetherness on the mat and are grateful for the gift of Aikido.

If these thoughts make you curious, then sign up for a trial lesson!

The Dojo

Kokoro Aikido Dojo

For the majority of our lessons we share the space  with Thomas Wiener's Taekwondo group. The dojo with separate changing rooms and showers is firmly lined with mats. We are only a 5-minute walk from the Prenzlauer Allee S-Bahn station.


There are also lessons in the Madang Center in the Kulturbrauerei - both for children and for adult beginners.

Our Style

Christian Tissier Sensei

The lessons in our dojo mainly follow the ideas of Christian Tissier Sensei (8th Dan Aikikai) from Paris. Tissier Sensei is probably the most important living Aikido teacher outside of Japan. His clear teaching style and his outstanding pedagogy have formed a whole generation of Aikidoka, of which we are proud to count ourselves a part of. Without him, Aikido in Europe would not be what it is today.

Another source of constant inspiration is Tsuruzu Miyamoto Sensei (8th Dan Aikikai) from Tokyo. His natural and humble way of teaching opens up completely new perspectives on Aikido. Miyamoto Sensei manages to create a traditional Japanese practice atmosphere while at the same time establishing individual contact with each of the students on his mat. His friendly humor is the perfect complement to his playful-serious way of teaching.

Tsuruzu Miyamoto Sensei

Yoko Okamoto Sensei

We have maintained a close connection with Yoko Okamoto Sensei (7th Dan Aikikai) in Kyoto for several years. She lived in the United States for many years and also in Paris during her studies. As a wanderer between worlds, she can uniquely combine the Western way of communicating with the core of the Japanese practice. On top of that, she's also just badass cool.

Finally, once a year we invite Jorma Lyly Sensei (6th Dan Aikikai) from Stockholm to Berlin to give a seminar here. His creativity and the freedom of his movements have become a constant for dozens of Berliners and hundreds of European aikidoka. His trademark is the integration of elements from the predecessor of Aikido, Daito-Ryu, as well as his endearingly eccentric way of explaining things.

Jorma Lyly Sensei

We also teach in English!

  Click on the flag for info.

Kokoro Aikido (Zentrale)
Grellstr. 74
10409 Berlin


Kokoro Aikido (Kulturbrauerei)

Knaackstr. 97

Hof 4 (Geb. 9.2) / 3. Stock

10435 Berlin