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Aikido/Difference between judo and aikido physics.


After studying judo for a while. I began to see dramatic similarities between aikido and judo. Ihave several questions in terms of their differences. I love aikido and believe in both arts. I absolutely respect aikido people.

Firstly both my instructor and myself have observed and found that aikido seem to use large circle techniques in an arc while judo tend to use small minor circular rotations around someone's centerline. Is this true and if so, How would this affect the centripetal force of the style's throws please?

Secondly the aikido leverage based movements focus on twisting the limbs in joint locks as well as throwing them unlike judo which just use leverage but doesn't seem to twist he limbs in any way. What is the purpose of these twists please?

Thirdly, I was into the concept of maii, and is there difference between the maii of judo and aikido please?

I am familiar with kuzushi concept. From a friend, he said that aikido need a committed attacker because they time themselves to blend in with the momentum of attack unlike judo which disrupts and use it to off balance someone, can aikido give off balance too please?

What do you think of pressure testing and randori in both judo and aikido? Do you think it is essential to application of physics in uncontrolled situations?

Finally I would like to learn some differences between the arts please. Or are they really too similar?

Thank you in advance. I strongly appreciate your help with all of these questions.

Thank you.


Good questions.

My former sensei was a one time coach for the US Olympic Judo team, back in the 70's.  He was first and foremost a Judoka.  Since Judo was and is pretty well defined he saw opportunities in Aikido that did not exist in Judo, so he founded his own ryu or style of Aikido that differed in some aspects from Tomiki encompassing aspects of Judo.  In fact we studied some Judo in our Aikido repertoire.  

To put some things in perspective.  First, I would have to say, that Aikido is not as physcially demanding.  We have nothing that compares to mat work or grappling and if you haven't noticed, there are a lot of Aikidoka that are rather portly.  I for my part gravitated to Aikido since my knees had taken a beating from years of running and other sports.  I did not think they would stand up to foot sweeps too well and other movements that inflicted a lot of lateral pressure on them.  This was born out when I discovered my sensi had had to have both his knees replaced.  While I was studying/teaching at the dojo he had them replaced for a second time.

My Sensei lamented the evolution of Judo, as it is practiced in competition today from an "art" of timing and balance to a strength based exercise in brawling.  When we were working on some judo moves I got interested and looked up clips on Utube and was appalled by what I saw in competition, up to and including the Olympics.  I saw none of the grace or finess I witnessed in the dojo.  He attributed it to the changes made in the sport by the Europeans.

You are right about the larger circles.  That is because of the distance that the techniques are excuted from.  Aikido is comprised first of empty hand sword movements, which expains the close connection between aikido and the use of the sword.  I believe Tomiki, who by the way wanted to do for Aikido what the Kodakan did for Judo, that is codify the art into an easily understood system.  He got Ueshiba's blessing,but when he was finished, it was rejected by Ueshiba's inner circle.

A digression if I may.  I attended law school years ago and I see parallels in the mindset of Ueshiba's inner circle with Attorneys and priests.   We trained for weeks just to understand how to use the law library and make sense out of the law books.  The early catholic church fought any attempts to translate the bible from greek and latin to more accessble languages like german.  The first German author to translate it into German was burned.

Knowledge is power.  If you control the knowledge, you retain the power.

It is easy to see why they did not want their system to be put into an easily understood set of kata.  Tomiki therefore released his own system.  Having studied a offshoot of Tomiki, and compared it to the Ueshiba style, you are hard pressed to make a meaningful comparison.  The terminology is completely different, and the stress on fundamentals are different.  Usehiba style takes on a quasi religious aspect leaning on Ki alot, something we did not ever even discuss.  Ueshiba style has a dozen names for one movement covering a myriad of slight variations of the same thing.  To my mind that would slow the learning by a non japanese speaker and would take years to learn.  See where I'm going?  Tomiki boiled down all the useless minutiae into a usable system that was a lot easier to learn, and got rid of all the mystical nonsense and taught more from the aspect of physics, although he did not come out and say it, the astute student could figure it out for himself without a lot of belly button contemplation getting in the way.

The size of the circles differ with who it teaching the techniques, and whether they are apply the concept of Kihara or constant movement or from a static position.  If using kihara, and keeping the correct distance, the centrifical force of the throw is increased as opposed to making the throw from close in in a smaller circle.  That is not to say the smaller circle throws are not as powerful, I believe the power is directed more towards the mat thrusting the uke downward.  In the case of Aikido, the uke falls and is not thrown per se.

It is impossible to execute a technique or throw using strength while using kihara and visa versa.  I order to use strength is is necessary to plant oneself.  To demonstrate this, try lifting something while moving, you can't.  You must plant your feet in order to lift or exert force up or down.  So in a state of movement just about all you can do is redirect your opponent's energy and motion to a point where he is unbalanced and you can use his own force against him.  There is a third option to exert force and that is laterally.  Our Shomen-ate or front strike is not really a blow, but the application of force generated by movement of mass, your body weight in a falling step forward and apply that force with an unbendable arm (slightly flexed but held rigid by muscle tension) the arm becomes a battering ram, that when it collides with an opponent moving in the opposite direction overcomes his forward motion and causes part of him to reverse in mid air and turns him on his head.  I weigh 250lbs and my forward drop step covers two feet in about a second.  So that is at least 500 foot pounds of force applied to my opponents face while his lower body is traveling foward at 2 ft per second.  The results are pretty dramatic. I have had to use this on the street and my opponent who was in the middle of throwing a punch, was stood on his head.  His body pivoted at the height of where his face was, and he fell the five feed down onto his head.  Luckily or me his shoulder hit the fender of a car and he was not severly injured.  The throw was so dramatic, that the two guys who were with him and ready to back him up, put their hands up and backed away, leaving their "buddy" lying where he fell.

My point is in our system, we do not use strength but force.  There is a difference.  The circular force will sometimes be dissipated by the distance the uke travels outward from the throw before he falls.  In Aikido, we do count on the fact that not everyone knows how to do a break fall, or fall without hurting themselves.  I am not speaking about in the dojo, but on the street.  A large circular throw for an judoka or another akidoka would only result in him executing a breakfall, whereas someone who is unfamiliar with how to breakfall would fall and crack his head on the pavement being unable to control the power of the throw.

Some of the bigger circular techniques are used to set the opponent into an uncontrolled state that can then lead to a smaller more directed throw where the uke is directed into the ground.

For instance, Ushiro-ate or back throw can be executed in the manner of a matador avoiding a charging bull, by stepping out of the path of attack, and hooking the opponents shoulders, as he goes by and then executing a falling back step pivot.  This results in you doing to the opponents shoulders what I did to my opponents face with Shomen-ate.  His shoulders are propelled backward and while his lower body continues forward, he goes horizontal a shoulder height and slams into the ground.   It is hard to control what your head does at that point even if you know how to breakfall.  We normally did all attacks at slow speed, to mitigate the power.  On a few occasions we would allow a demonstration of the power of the techniques at full speed and it was sobering.  We had a fully sprung floor over closed cell foam matts covered with canvas and the 5 foot fall flat on your back stunned us and we were prepared for it.  It was impossible to bo a break fall.  

Some Akidoka execute the move by pulling down, and powering the uke into the mat, this breaks kihara because to do that they would have to plant their feet in order to execute the push downward.

Sometimes the larger circular movements are a prelude to a movement to reverse direction setting up a controlled collision, where the Tori can use the force of his movement against a vulnerable point of the moving Uke.  A good illustration is the closeline you see Steve Segal use in a lot of his movies, where he is slinging his opponent is an circle only to reverse his direction with his curved arm open and sweeping through the neck of his opponent causing him to do a flip onto his head.  We do that technique in less dramatic and violent style but turnimg the opponent as we too pivot, then closeing in a smaller circle, capture his head and in one continous motion take the Uke into a back fall as he cannot regain his balance with us controling his head, and his head dropps down and through our curved arm as he falls to the ground in a back fall.  That is at slow speed, at full speed it would likely be as dramatic and violent as you see in the films.

Joint locks.

We do not use joint locks in large part to execute a throw, but only after the throw is completed to restrain the opponent.  The arm bar for instance IS the technique, you use it to bring your opponent to their knees.  In all honesty in a fight you would just go ahead and break the guys elbow and be done with it.  While you hold the armbar, his buddies might be doing an number on his head.  This is where the kata and the real world part ways.  Kata have to have a nice ending.  Not so in a real fight.  So, you break his elbow and then look around for the next guy.

Looking at a lot of the popular Tomiki books and the way it is taught, a lot of them use strength and use joint torque to execute a throw. In order to do this you need to plant your feet to apply power. That stops you in your tracks and defeats kihara.

Kote Gaeshi or turning throw is an example, it looks like you grab the opponents hand as your pivot twisting the wrist toward the opponents chest and around to the outside by apply pressure to the back of the twisted hand.  The pressure is not what you use to make the throw, at least not correctly.  But all to many Akidoka do it that way, resorting to force.  The correct way is to use the hand grab to control your opponent in order to control him until he takes his next step, then you extend your step only slightly longer at which point he is completely unbalanced and had no where to go but out and down.  The slight pressure you have on his hand directs him in the foreward flip fall.  Once again, most books show this throw executed by the Tori "cranking" on the wrist to execute the technique.  Doing it this way can result in a lot of injured wrists in the dojo and a lot of unpopular akidoka no one wants to work with.  I had mine injured by a senior Akidoka who should have known better but was compensating for his lack of mobility as he got older and fatter.

So in a word the locks and twist serve two purposes, control leading into the throw and control after the throw.  If control is maintained through the fall, one might be in position of further incapacitate the opponent by dislocating a shoulder or something after the opponent is on the ground.  They should not play a part in forcing the uke to take the fall, and if they are, they are being executed by a poor Akidoka, compensating for his lack of finess  and timing with power and brute strength.

Maii for Akido is two unbendable arms distance so roughly 6 feet.  When your opponent closes that distance, you should be in motion.  So if we were sparring we would hold up our arms to establish maii, then when you as Uke started to move, maii would be broken and I would begin to move.  Someting I told my students is you have to have already made up your mind that you are fighting, or retreating, there is no time to second guess.  The idea is to catch your opponent on his first foot fall inside of maii, where he is poised on the ball of his foot,   This is the point where you take the Uke into kuzushi. Or it may be the point where he pushes the akidoka and the Akidoka blends with his force and takes him into a circle keeping him in kuzushi until he applies a forehead sweep or a back drop to the shoulders.

From that point you can turn him and keep him unbalanced with ease. If you miss that instance, the best you can do is keep moving with him in order to try to catch him on the next one.  You do not use force with force but blend with him if he pushes, you go with the push to maintain him in kuzushi, if he pulls you go with the pull, you don't give him anything solid to hold onto to regain his balance once he enters kuzushi.

Not sure what you mean by pressure testing.  If I follow you correctly, I think you are speaking about what we call "soft" or "hard" which I referred to above.  Soft in the touch and application of the techniques does not equate to the outcome, it refers to the touch of the Tori, and how he moves and executes the techniques, whereas, "hard" refers to the application of force, cranking the joints, executing using strength rather than finess.

Our randori was done in virtual slow motion, relying on putting the opponent in a position that he knew he could not excape from and at which time he would be thrown.  There was no room for ego.  I am reminded of playing cowboys and indians as a kid where their was always one kid who would always "yell you missed, missed" and never admit or let himself be hit by imaginary bullets.  The same occurs in the dojo, where one or two guys in randori will never admit that they were "shot".  It is an ego thing with them and they always have to end up on top, where it should be a learning experience.  Their egos will always prevent them from getting very good.

By physics I don't just limit it to application of force, but gravity too.  In aikido, we dont' throw in the sense that you do in judo, nor do we grapple.  If we get in a grapple situation, something has gone horribly wrong.  We rely on distance, movement, and timing.

We then rely on the physics of our opponents movement,speed and mass to work for us by applying the sum of those things to magnify the force of the technique on his physical person.

A slow motion Shomen-ate or Ushiro-ate results in a nice controlled fall by Uke.  On the street at full speed the same technique results in a high speed and out of control fall on the part of Uke that cannot truly be defended against or mitigated.

YOur friend is absolutely correct about commited attack.  I told my students, you have to simulate a committed attack.  Aikido is defensive.  If the opponent does not attack, you just stand there and trade insults.  It is only when the opponent attacks that you can do anything.

You could probably do Osoto-gari on a stationary person but it works much better when they are moving toward you in motion right?  Same for Aikido.  I could force some thing but by doing so, I give up all my advantages and close on a stationary opponent who can punch, kick or close to grapple when I do so.  I'd rather stand off and make him move to get the full advantage of all the tools in my toolbox.

In some classes I would see half hearted attacks by Uke and would tell them, make a committed attack because that is the only way Tori can get you into kuzushi without using force.  An attacker is not going to throw a punch flat footed.  They will step into the punch and poise on their forward foot.  Without a committed attack, Tori cannot learn the timing that he needs to learn.  He needs to recognize that split second in time where the opponent has entered unbalance, and the entrance to kuzushi is open for Tori to exploit.  I would demonstrate, how the technique would feel when the timeing was right or if it was missed.  Everyone then understood its importance.

One of the things I learned was how badly some people picked up things, learning just from rote.  A lot of sensei learned techniques and then made them their own, but sadly what they learned had been modified and changed by their teachers and so over time was modified and changed in the dojo that after three or four generations of teacher, they bore little resemblance to the original  technique.  Being a scientist by training I deconstructed the techniques taught to me to see if in fact they would actually work, then researched them and found out that a lot of them were being taught to me wrong.  So I corrected them and if the higher ranks thought I was doing it wrong, I would demonstrate to them that what I was doing was actually the correct way.  They were simply doing it as they had been taught without question.  I researched the techniques on DVD of the way they were executed by Sensei.

For instance one of our knife defence techniques would only work if you took your opponent to unbalance to the outside then pivoted under his arm as he sought to regain balance,  if you didn't do this, then you left yourself open to a knife thrust in the back as you did your turn.  Without the unbalance, you were essentially doing a turn in front of him and he could stick his knife in your kidney.  The unbalance was critical, but no one was doing it, it had gotten dropped because ukes were being too compliant, and too eager not to mess up Tori's execution, so it became some lame dance with no resemblance to the real world.  You see a lot of that, and too many dojos foster it, by imposing draconian hiearchy bullshit, where everyone lives in fear of the sensei or the higher ranks who can do no wrong.  Without any versimilitude, a technique ends up looking like the bullshit kungfu dancing you see in the Chinese movies, where they jump around lunging and jumping like they had a jalepeno pepper shoved up their ass.

I've droned on long enough.  If I didn't cover all the points, I appologize.  We can continue the discussion if you like in another question.



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Keith Patton


I can answer questions regarding Aikido, particularly a highly advanced form of Tomiki Aikido, primarily concerned with self defence in real situations. I can address the basic techniques, releases, and the advanced kata as well as high level concepts of constant movement (kihara), balance breaking (kuzushi), internalization of techniques and chaining of techniques. Can also offer guidance in what to look for in selecting a dojo and an instructor.


I have been recognized for my skill in teaching new students and raising them to a high level of proficiency in a short time. As a trained scientist I like to reduce the Aikido techniques to their basic physics enabling a new student to see the essence of the technique.

Bachelor of Science and Master of Science. 26 years experience in the petroleum industry as well as mentoring and teaching new scientists and non-technical co-workers. Also Teaching at the college level.

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