“Leading” momentum – how realistic is it?


There are a great many “projections” or throws in the traditional martial arts (particularly in aikido) that focus on “leading” the momentum of the opponent – that is to say, continuing and redirecting the momentum of your opponent rather than opposing it.

I have a great admiration for this concept both philosophically and technically. But just how “practical” is it? In other words, what are your chances of “leading” the momentum of an opponent in a real civilian defence scenario?

Before I attempt to answer this question, let me first attempt to explain and describe the art and science of “leading” momentum.

Tai no henko – “body blending” as the essence of leading momentum

The concept behind “leading” is to use your opponent’s momentum against him or her: the harder your opponent tries to attack, the more this is redirected back to him or her.

I love this concept, both philosophically and pragmatically. I have previously discussed my inclination towards Daoist philosophy, in particular the concept of wu-wei (“going with the flow”). Indeed, it is the title of this blog. I firmly believe that optimal conflict management lies in following the lines of least resistance – whether that conflict is physical or just verbal.

A basic exercise used in aikido to introduce a student to the lines of least resistance is the exercise known as “tai no henko” or “body blending”. I illustrate the exercise below:

Tai no henko or “hiraki ashi” – a basic exercise to introduce students to “going with the flow”

You will note from the above video that the central concept behind tai no henko is the footwork known as “hiraki ashi”. This footwork involves 2 distinct actions:
(1) a step towards your opponent (irimi); then
(2) a turning action (tenkan).

Irimi – the necessity of entering

The initial step in towards your opponent is crucial to “leading” his or her momentum because it permits you to intercept the attack in its outward phase. This step towards your opponent is called “irimi” (entering) in Japanese.

Why is irimi so important? Quite simply, you need to catch your opponent mid-stride. If you catch him or her too early (ie. before your opponent builds up sufficient momentum) you might end up pulling rather than “leading” or “redirecting”. If you catch your opponent too late, the forward momentum will have been exhausted. Once again, you will end up pulling your opponent rather than “leading” him or her. The goal is to catch your opponent at the “sweet spot”.

Tenkan – the redirection

Once you have stepped in towards your opponent and intercepted his or her attack, you must then redirect it. This can be achieved through turning around while pivoting on the foot that stepped forwards. To quote the founder of aikido, Morihei Ueshiba:1

“In this sense, there is no opponent in aikido. Even if you have an opponent, he becomes a part of you, a partner you control only.”

I have often heard that in executing the tenkan, the aikidoka is metaphorically turning around to “see the world from the attacker’s perspective”.

But it is important to remember that "tai no henko" is, in itself, not a technique; it is an exercise that teaches you the important principles of irimi and tenkan. How are those principles are applied in particular techniques? Let me focus on one example - the aikido projection known as "irimi nage":

“Leading” momentum and irimi nage

I think the best example of leading momentum is to be found in aikido's irimi nage (entering throw). I have cropped the adjacent gif from a video that is on Youtube, but there are literally thousands of good examples.

You will note that the attacker steps forward with an attack. Rather than step away from the attack, the defender steps in towards it, intercepting it at an early stage (irimi). The defender then continues the forward (and downward) momentum, redirecting it with a circular turn of the body (tenkan). But this is just the first phase of the classical irimi nage demonstrated here:

As the redirection in the first phase is exhausted, the attacker starts to recover his balance, only to find that this act of recovery (in this case standing up and resisting the forward momentum) is itself redirected with the powerful forearm/body projection - a projection I consider the defining element of the irimi nage.

Many people mistakenly think this second phase is equivalent to "clotheslining" your opponent. However the use of the arm in this phase (also found in "tenchi nage" or "heaven and earth throw") relies on correct application of a sophisticated projection - not just a crude ramming home of the forearm across the neck.

Indeed it is possible by-pass the first phase and go straight to the second. Consider the adjacent gif of me performing our school's version of "irimi nage":

You will note that there is no initial "leading" of the opponent's forward momentum. Instead, I focus on the fact that after my initial entry, the attacker is likely to start reversing his momentum (the second phase) so I cut straight to the second phase projection, using the irimi nage to lead his reversed momentum.

Is this better - or just different? It is noteworthy that in all my hard and fast sparring, I have only ever applied our "shortened" variant of irimi nage: I have never managed to apply the first phase of the classical aikido version, namely leading the opponent's forward momentum with a tenkan movement. But then again, one might validly point out that we are talking about sparring - not real fighting. Is there a role for the tenkan in leading the initial forward momentum in a civilian defence scenario? My answer to that is definitely yes - but with some important qualifications:

Tenkan and its application to committed attacks

A tenkan can indeed be applied to continue an attacker's inital forward movement. In the adjacent gif I demonstrate the tenkan when applied in isolation (ie. not as part of some other throw).2 You will notice that I enter and turn, catching my attacker's forward motion as our respective central axes cross.

However it is my view that the instances in which tenkan nage can be applied are very limited.

First, it is my experience that tenkan only works against a very committed, charging attack. In traditional Okinawan and Japanese arts we are accustomed to seeing such attacks used as a platform for practice of techniques. I will save to another time a discussion of the merits and limitations of such a platform since this is a topic onto itself. Suffice it to say, arts such as karate and aikido are traditionally applied in practice against single attacks launched from a committed step (ippon kumite). The attacker is initially out of range, but closes the gap with his or her step.

Second, the tenkan is only possible if you enter closely to your opponent and, essentially, meet him/her body to body. To redirect an oncoming force you need to work like a spinning top, moving into the centre - where the speed is slow enough to give you the opportunity of catching the momentum and "going with it".

By contrast, attempting to catch and continue/redirect the extremity of a limb (eg. a hand or foot) is, in my experience, practically impossible given the usual speed at which an attacking limb is travelling at the point of interception, the speed of typical human reaction and the fact that you are not entering into, and utilising, the centre of his/her "circle".3

With these provisos, I think it is quite possible to enter and redirect a committed attack. However given that such attacks are rarely used in sparring (whether one spars in a modern combat sports fashion, using the sport karate/taekwondo method or our randori method) it is unsurprising that tenkan is also rarely applied in sparring.

At this point I will observe that the applicability of the tenkan doesn't rely solely on a stepping attack (of the kind seen in ippon kumite). Rather, tenkan will work against any sufficiently committed attack. For example a powerful cross punch (with a follow through) is capable of being countered with a tenkan - with or without a step. Consider the video below from 1:00 onwards:

In this video I demonstrate the "tenkan nage" against a right cross or haymaker from about 1:00 onwards

In sparring your partner is unlikely to be trying to hit you with a full power cross or haymaker. So again, it is unlikely that you will have the opportunity to apply a tenkan.

However the fact remains: tenkan is unlikely to work against anything except fully committed punches launched out of range. Even in the above video my partner is throwing the right cross from a distance. It is my experience that when punches are thrown within the melee range you simply don't have the time to catch the outward momentum and continue it. You are limited by the simple logistics of your reaction speed and the shorter time interval in question.

"Leading" reversed momentum

Accordingly it is my view that in respect of most attacks, you will only have the opportunity to intercept the attack - not continue its forward momentum. This interception will usually take the form of a block or deflection. Having made limb to limb contact with the deflection, your opponent will generally cease his or her forward momentum. And as discussed, the time intervals and reaction speeds in the melee range are such that it is near-on impossible to catch your opponent's forward momentum before this happens. What this means is that you are then limited to "leading" the reversed momentum. Like a wave, your opponent with crash and immediately draw back. In the spirit of "wu-wei" or "aiki" you should "go with the flow" and use the inevitable "withdrawal" against your opponent.

A good example of this is to be found in my variant on irimi nage above (in which I make no attempt to continue my attacker's forward momentum, but simply "enhance" his retreat).

In my experience, if you are able to catch part of an attacker's forward momentum, it will most likely only be enough to briefly destablise him or her, before the "reversal": the forward momentum will be insufficient to permit a full "tenkan" throw.

Accordingly the adjacent gif constitutes another variant on the traditional aikido "irimi nage" that I have, from time to time, managed to apply in sparring. You will note that I step into the attack and redirect it. However my attacker quickly realises he has been wrongfooted and starts to resist the redirection, whereupon I "lead" his reversed momentum.

This is quite similar in concept to the irimi nage depicted at the beginning of this article, however it is no where near as "grand" in scope. The control and redirection of the forward momentum is only partial, hence the throw is really quite "abbreviated" as compared to the classical irimi nage. You will also note that I don't have the time to apply the standard forearm projection of the irimi nage (the "clothesline"): I lead my attacker's reversed momentum with as little movement on my part as possible, so as not to lose control of that momentum.


Accordingly I think it is possible to "lead" an attacker's momentum in a civilian defence scenario - maybe not in the way the classical aikido throws are practised, but with the same principles in mind.

Leading the forward momentum of your attacker is possible, but problematic. The circumstances in which this will be possible are, I think, limited to very committed attacks that start out of range and have some element of "follow through".

Leading the reverse momentum is however an entirely different kettle of fish. The initial contact you establish when your defence "meets" an attack will give you the kinaesthetic awareness needed to deal with any reversal of momentum. It is important to note that by "reversal" I don't mean to imply a complete withdrawal or the exact opposite movement to the inital attack - merely a cessation of the momentum of the initial attack and the commencement of some other movement. This might comprise a withdrawal or retraction, or it might involve momentum along some other vector. Either way, the initial momentum is no longer pursued.

I think that leading such a "reversed" momentum is not only possible - it is quite intuitive and effective. Accordingly I make this the primary focus of my own projections - and I leave leading the forward momentum to the occasional instance. I feel this approach has the potential to turn the beautiful philosophy/theory of aikido into a hard-nosed, pragmatic fighting system.


1. See this article or this article.
2. I call this throw "tenkan nage" to distinguish it from irimi nage etc.
3. A good example of the pitfalls of attempting to catch, and continue the momentum of, a hand/fist is to be found in the projection known as "kote gaeshi" or "wrist out-turn throw" - which I plan to analyse in detail in a separate article.

Copyright © 2010 Dejan Djurdjevic