In An Introduction to Hanmi I wrote:
"When I first started to learn Matsubayashi-Ryu around 1975, [when executing a junzuki] we stood with our shoulders square and our tanden (below the belly button) facing the front (the direction we were punching). Our shoulders were essentially at a right angle to our punch.I was describing a junzuki in shizendachi (natural stance). The same comment would also apply to most blocks. Today, in my dojo, we do not block with our shoulders or tanden square to the front -- we are slanted in hanmi.
Today, we execute the same punch in the same stance, but with our shoulders almost at a diagonal and our tanden facing about a 45 degree angle (to the left). We call this position hanmi. Our shoulders are not square to the direction of the punch."
I was asked by a blog reader why there was a change from the square alignment to hanmi. There are several reasons.
First, when I was a beginner, it was natural that I would learn the most basic and simple form. As I advanced over the years, my method of generating power changed. As a beginner, I would say that I used 80% upper body strength and only 20% lower body strength. So I would essentially move into position and then try to "muscle" the technique.
Today, I would say that I am using 80% to 90% lower body strength. By the time I get into a desired postion, I will have already thrown the technique.
Using koshi is one of the most important aspects of Karate. However, it also not a good idea to teach beginners koshi too early or their form will suffer. It is better to teach them nice linear movements with precise stances and well defined movements.
As we advance, however, he must literally learn to tame the "whirlwind", abandon all fixed stances, and blur our movements from one to another. It is like the difference between the block printing we learn as children and the way we sign checks (in almost undecipherable squiggles) -- and yet the check it good.
Why square shoulders? Because it was good for beginners.
Why hanmi? Because it makes sense to use it when you can generate power with your lower body (in a narrow rotational angle).
If there is a problem it has to do with the progression of teaching. If a beginner moves a certain way, it is good. If an advanced student moves like a beginner, there is a problem.
A 9th dan once told me something interesting. He was talking about a 7th dan and he said "a 7th dan still has Karate to learn, you know."
A 7th dan still has Karate to learn. So does an 8th dan, I suspect.
My point, is that we learn one way as beginners, and different ways at each phase of our progress in the art. If even a 7th dan is still learning... well, it should not be surprising that our shoulder alignment might change many times during our training career.
The idea, ultimately is to be able to punch, block, and strike in any alignment, in any direction, with maximum power generated in an instant.
I should also clarify something. Around 1974, I began to learn Matsubayashi-Ryu. Since 2002, I have practiced the Kishaba Juku form of Shorin-Ryu. I do not practice or teach Matsubayashi-Ryu, so I cannot comment upon the techniques or methodologies of that system. I can really only speak about the way that I teach in my own dojo.
To me, Shorin-Ryu is Shorin-Ryu and Karate is Karate (I think that there is far too much emphasis on styles). I suspect that the issue of shoulder and tanden alignment is handled in a wide variety of ways.
At this point in time, we are practicing hanmi in my dojo, among many other principles.
But who knows what tomorrow may bring?
Charles C. Goodin