作用反作用の法則 (Sayō Hansayō no Hōsoku)

Newton's Third Law of Motion is universally translated into Japanese as Sayō Hansayō no Hōsoku: 作用反作用の法則

Literally translated, it means "The Law of Action and Reaction" (Sayō = Action, Hansayō = Reaction, Hōsoku = Law).

Breaking Down the Components

作用 (Sayō): The "Action" or the force applied to an object. In karate, this corresponds to you aggressively driving your foot down or into the floor. 

反作用 (Hansayō): The "Reaction" or the equal and opposite force pushed back. In training, this is the exact moment the floor pushes back up through your skeleton, creating 地面反力 (Jimen Hanryoku) or ‘Ground Reaction Force’, which I loosely refer to as ‘Ground Power’.

How to use it in context:

If a professional karate instructor or sports science text mentions Newton's third law globally, they will say:

「運動の第三法則」 (Undō no dai-san hōsoku) — "The Third Law of Motion".

「作用反作用の法則に従う」 (Sayō hansayō no hōsoku ni shitagau) — "To follow/obey the law of action and reaction."

  押忍！

André 

©️ André Bertel. Ōita City, Japan (2026).

Oliver Schömburg returns to Ōita

 Oliver Schömburg Sensei (3rd Dan) from Ahrensburg, Germany visited Ōita for several days. As always, it was really great to catch up with him.

I encouraged his on-going study of 半月 (Hangetsu) originally known as セイシャン (Seishan). Such traditional Karatedō kata are packed with rich budō knowledge handed down from the past. 

For higher level karateka, kata which are popular in competitions means very little. Accordingly, as one advances in skill, particularly in their post-competition years, it is “…no longer about merely seeking external performance but, rather, about finding Bujutsu waza and tactics from any given kata and seeking to master these for actual effectiveness”. This is, in fact, the meaning of mastery of kata and karate in general.

I’d like to expand on this. Kata and karate techniques which cannot be applied in a freestyle context, irrespective of however good they may look, are merely ‘photocopies of karate’. 

To conclude, it was wonderful to share some karate with Oliver again; moreover, cooperate together for a project, which I will leave for Oliver to detail in the near future.

Oliver, it was wonderful to catch up and fun to hang out. My hope is that you continue your study of Hangetsu, strength and impact training. The girls and I wish you a safe and very enjoyable flight home from Ōita to Hamburg.

More information coming later, so stay tuned!!

押忍！

恩道礼 (アンドレ バーテル)

©️ André Bertel. Ōita City, Japan (2026).

The 70 Official I.K.S (International Karate-Dō Shōtōkan) Kata

Many people outside of the IKS do not understand the vast number of Kata that we have and preserve in our organization.

This number is not for superficial learning but, rather, to give our members more options to select kata best suited for themselves. They also expand our technical knowledge, and for those who enjoy kata, they bring much enjoyment in daily training. Please note you can click on the following images below to see each of official IKS kata names in both Kanji and English.

Ironically, Dan grades in our group, only need to two or three kata.

For example, some karateka with high Dan only practice one of the Heian, and one of the Tekki, and perhaps say, Jion. The IKS has no compulsory kata, except the five Heian and Tekki Shodan for kyu gradings. The number of kata one practices is up to each individual! Of course, quality is what matters most, and also motivation.

Again, in regard to the aforementioned point of 'motivation', other karateka greatly enjoy learning and perfecting many kata (in addition to the essential specialization in just a handful). Of course, those who are active competitors focus on the kata required for success in this field. 

Therefore, again, the vast number of kata are purely to give more Budō options. The International Karate-Dō Shōtōkan is an organization that serves its members, not the other way around.

Let's ENJOY the Way of Karate-Dō together!

押忍！

©️ International Karate-Dō Shōtōkan HQ. 

Ōita City, Japan (2026).

Renshūsei from Bern, SWITZERLAND: Part Two (Kumite)

Beat Frauchiger, from Bern (Switzerland), specifically asked for Jiyū Kumite training.  

Accordingly, here are some images of the Kumite training. The images are to remind Beat of the key points I taught him during his time here as a Renshūsei.

Like with all first-time Renshūsei, who specifically request Jiyū Kumite, when sparring I limit my types of attacks, to allow them to build familiarity with them. Then I subtly adjust them, so the trainee cannot defend against them. As the trainee's skill advances, I gradually increase the number of techniques I use, introduce more variations/adaptations, and progressively speed up without compromising safety. In this way, skills and confidence is built up without the fear of injury. 

I wish you the very best Beat and hope that you can develop your skill in Kumite from now. Best regards and good luck, 押忍！

Haitō uchi

Closely slipping techniques to apply DEAI-WAZA makes defense nearly impossible for the oppoent.

As the opponent adjusts their position land your kick.

Punching to the throat.

The axing mawashi-geri impacting with the shin.

The classical mawashi-geri with the 'ball of the foot'.

My 'tokui' specialty in Free sparring: DEAI-WAZA.

There is no contact here, as you can see Beat is laughing. It is just a gentle push with the fist (to verify the correct distance). All too often karateka throw their techniques from 'point fighting distance', which has no relationship to Budō Karate.

Kaiten shutō uchi to the carotid artery.

In Jiyū Kumite train light and with control to avoid injuries and progressively develop skill. Couple this with full contact training on impact shields, the sandbag and other training tools. In this way we can safely practice and develop the necessary skills, speed, timing and power.

©️ André Bertel. Oita City, Japan (2026).

Renshūsei from Bern, SWITZERLAND: Part One (Kihon and Kata)

Beat Frauchiger who is a Nidan from Bern, Switzerland, came for four sessions as a Renshūsei. It was great to have him here and see him progressively improve his karate.

Rather than go into what I taught, here are some images from the Kihon and Kata covered. Please note that 'Part Two' will cover Kumite.

I should add that his request was to study Rōshū and Rakuyō, which of course I obliged. But like everyone else, I stressed the importance of the core Shōtōkan kata, especially Heian for one's foundation.

In Shōtōkan-Ryū, Heian Shodan (Pinan Nidan) is most important, coupled with any of the three Tekki; furthermore, any kata from Bassai (Dai), Kanku (Dai), Jitte, Hangetsu, Enpi, Gankaku and/or Jion.

Overall, I'd like to wish Beat the very best in his karate development and for his remaining time here in Japan. With serious practice of the points covered, you will greatly improve from now!

押忍！

©️ André Bertel. Oita City, Japan (2026).

Renshūsei from Geelong, AUSTRALIA

Pieter de Koning Sensei (Sandan) and his lovely wife Lezanne (who recently attained her Shodan) came to meet and train as Renshūsei here in Ōita.

From South Africa, their dōjō ‘WSKF Karate Geelong’ has classes for beginners and experience karateka, both children and adults, in Belmont. For those interested in training please contact Pieter Sensei at: info@karategeelong.com.au

Furthermore, here is a link to their club website: www.karategeelong.com.au

Insofar as their Renshūsei training is concerned, the focus was on core the traditional Japanese Shōtōkan 基本(kihon). This was done via several of the central kihonwaza in our style. 平安初段 (Heian Shodan) was extensively utilized as a foundational reference point for both 型 (Kata) and 組手 (Kumite).

As always in my teaching, the overarching theme was my teacher, Shuseki-Shihan Tetsuhiko Asai's 自然空手 'SHIZEN KARATE' or 'Natural Karate'.

It was great working with Pieter and Lezanne, as they are such nice people and very studious in their karate practice. Accordingly, it made it easier for me to impart several critical aspects of Shōtōkan-Ryū. Outside of the training it was also great spending some time together!

Overall, I want to wish Pieter Sensei and Lezanne the best in health, happiness and in their Karate-Dō training. I look forward to seeing you both again in the future!

押忍！

AB

©️ André Bertel. Oita City, Japan (2026).

筋肉は使わないと落ちる

Concluding my self-practice today with some jumping training for explosiveness.

筋肉は使わないと落ちる literally means “Muscles drop/shrink if you don't use them” while, while slightly different from the English saying, “Use it or lose it”, conveys the same point.

Fortunately, in ‘traditional karate-dō’ being in one’s 50s, as I am, is still very young.

Seeing my seniors in their 60’s, 70’s and older, it is obvious that those who constantly practice karate “…irrespective of injury or illness, continue to defy age and their respective ailments”.

Practicing tobi yoko-geri today (to conclude my session) reminds me that I’m still just a young man in Karate-Dō… as long as I continue training.

After 45 years of karate, I look to the inspiration of my seniors, especially here in Japan,  some of whom are now in their 90s and still train!

In sum, irrespective of your age: KEEP TRAINING! And even if you’ve stopped, if you listen to your body, you can always come back.

I am reminded of a statement by Tanaka Masahiko Sensei: “Karate-Do is Lifetime Budō”.

押忍!

アンドレ バーテル

©️ André Bertel. Oita City, Japan (October 23rd, 2026).