I have noticed a couple of distinct ways of applying seoi nage. In the first, uke is fixed to tori's back, projected forwards and over to the ground.
The second is to pull uke down over tori's back and drive up underneath by straightening the legs, similar to the lift in o goshi. There is more emphasis on the bottom of the circle than the first method.
Please can we have a masterclass on seoi nage?
Hmm, I don't know if this will turn into a master class. A couple of years ago I was asked to extensively look into the physics and didactics of a jûdô throw and seoi-nage was one of the options, but I decide to write about a different one, for a number of reasons, one of them being that it has been for near 60 years a specialty of my club and of several of my teachers. I could have chosen seoi-nage too, but I didn't.
However, maybe we shouldn't reinvent the wheel. Seoi-nage, together with ô-soto-gari and uchi-mata are the three most studied jûdô techniques by biomechanists and jûdô-technical specialists. It has been the subject of theses, specialized biomechanical papers, and there exists an excellent Japanese videotape devoted to nothing else.
As with all throwing techniques in jûdô, there is the science and there is the traditional. pedagogy and didactic approach. Again, for this throw, the two are different. The throw or similar appears in many Japanese traditional martial arts.
The basic science behind it is simple, and the scientific requirements amount to just a few things:
- the distance between the 2 opponents must be closed; it is not possible to perform seoi-nage if one opponent is in one corner of the tatami and the other in the other corner.
- as the distance is closed there will be a 'collision' of bodies, the term 'collision' used here as a physics term.
- the displacement of the couple formed by the two opponents has to be momentarily stopped because seoi-nage is a lever throw and it is not possible to perform a lever throw without stopping, even if this halt is just a fraction of a second. During that instant the fulcrum is established and the levers applied. Kuzushi scientifically does not exist as a separate phase and is part of the execution of the throw. By applying the lever the center of mass is displaced in such a way that recovery is not possible (= loss of balance).
That's it, scientifically. The only difference is that excellent jûdô excel in choosing the moment, in applying the most efficient position of the fulcrum and use of levers, and in application of power they can apply, and in strategic thinking, and speed of action.
In terms of didactic approach, things are different and jûdô postulates phases so that students can compartmentalize. Through instruction from a teacher strategies can be tried out to optimize debana, and this will also increase with experience. Ways of hairi-kata (= how to enter the throw) can be taught, learnt and practised, as well as a plethora on how and where to construct the fulcrum, the levers and manipulate these to the most ideal for your body, your way of judo and physical abilities, that the properties of the opponent. In jûdô-speak, these are things we know such as coordination, control, etc.
There are many, many ways for doing this, some are better, some are worse, some are just different, some appeal to certain perks or to additional scientific or knowledge. For example, a rotational (spiraling seoi-nage) is more effective in the sense that it is more difficult to resist for uke, because a human's ability to resist rotational kuzushi is much impaired in comparison with linear kuzushi. Also force applied in a rotational mode (torque) has peculiarities when compared to following a linear trajectory. That being said, there are may other factors and characteristics on which an athlete can focus despite Koga Toshihiko usually doing rather linear trajectory seoi-nage he was very successful with it since obviously he excelled in optimizing many other technical and strategic aspects.
There is thus not one or two ways to do it which would be the only correct ways. Rather one has to look at an individual and where the problems are and correct those towards a mode that likely is the easiest or most effective for him to do. A superb jûdôka or with specific features may be able to do things which others can't or which others label as mistakes. It's a matter of coordination, debana and strategy, and if you master these things with such a degree of superiority, you may be able to perform the most aberrant or unusual seoi-nage with great success. The better jûdôka will also (unknowingly) apply the scientific concept but the better the jûdô the more 'efficient' its application becomes, i.e. literally a greater effect with a lesser effort.