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Judo/How would you realistically use judo physics against edged weapons? Or does it totally not work for that type of fight?


Hello Mr. Ellis. Thank you very much for your time. My question is kinda a bit more off to the martial art side of judo than the competitive side so sorry if it's a bit winded......

First of all, I definitely agree that the first line against any weapons based on pressure of force over area requires you to not be there in the first place or if desperate, gain as much of distance and time as possible since pressure doesn't need distance unlike kinetic energy from say punches.

Now I did some research on old Kodokan Judo and to quote Jigoro Kano directly from 'The Policy of Kodokan-Collection of Kano. J's writings.' against strikes seems to be " approach in a manner to defend yourself against the opponent’s stab and kick." Which suggests that judo does require footwork and evasion to off balance and attack the attack instead of deflections or blockings which helps but is not the main aim.

I have also researched on Kyuzo Mifune and to quote him from his writings "“Almost all ancient schools of jujutsu have tekubi-waza
(wrist techniques: kote-gaeshi, kote-hineri, etc.), and atemi-waza
(striking and kicking techniques) as well" that to defend against such attacks ideally by "applying a leg or hip throw upon the moment of contact" before they even had time to mess with the in-fighting joint locks and strikes.

I was wondering if the same movements can be applied and practiced on edged weapons. Mainly because we know that E= 1/2mv^2 which is the basis behind what makes blunt blows e.g. the atemi waza effective and that distance is usually needed to build up the energy for an effective strike or in close quarters, there's still things that needs to speed up the punch.

Or as both masters put it "you step forward
to his right side whilst you pull the opponent’s right wrist or
sleeve. In this case, the opponent can’t attack you because his
right hand is controlled by the grabbing.The opponent’s
left hand is free to attack, but it is far to reach you so that you are in little danger."

While I do agree with the majority of it. There's certain things I just don't want to use against an edged weapon. Namely the strategy of 'grabbing,' seems to be a debate for most experts in that in knife attacks or violent situations, they just cannot effectively grab onto the armed limb or the attacker could switch knife to the other hand. The other thing I don't quite agree with is if you are truely safe from an edged weapon even if that hand is a 'little too far to reach you.' As edged weapon rely on pressure more than kinetic energy, would it still inflict stab injuries regardless.

So what's your opinion on the evasion and off balance tactics in that type of situation please.

Also do you feel that the Kime no Kata and Goshin Jutsu are a bit flawed in that they are now-a-days rote learned like a dance instead of a full universally applicable study?

Thanks for your support. All the best.

Let me start this answer by stating any martial art taught well will say don't put yourself in a position where you will have to use it especially against a weapon.

In the Judo/Jujitsu (Pre WW II Judo) class, we have practice several moves against edged weapon.  So it can be used against an attacker with an edged weapon using Judo (Pre WW II Judo, which has strikes and the ability to apply pressure other than elbow joint). It does deal with body movement and balance, keeping yours while causing off balance of your opponent. So yes it can be effective.

It depends on the Kata is practiced, while it is true most practice it as a dance and not as an effective self defense move.  It can be done in showing 1 option in a self defense way.  And as someone that has trained with several different people in Kime No Kata, it can be effective and again gives 1 option.

I think I answered your questions.

Yours in Judo,
David J. Ellis  


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David J. Ellis


David has been a state champion in both regular competition (shiai) and in forms (kata). David is currently an USA Judo National Referee. David Ellis has studied Judo continuously since 1975, and is currently a Yodan (fourth degree black belt). David has been a head Judo Instructor (aprox. 11 years) and an assistant Judo Instructor (over 15 years). David is currently the Head Assistant Instructor and Head Kata Instructor of Samurai Judo & Jujitsu in Melbourne, Florida


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