Sanchin ignites many different things in different people. Rather than debate another never ending topic I would just like to make a few points.
First, there are arts that do not practice anything like Sanchin and they are as effective as those arts who do.
Movement is movement. The idea that some movements are more basic than others seems flawed. There are those who choose to use one movement over other movements.
Something comes toward you, a grab, jab, strike, kick. Regardless something is moving in your direction.
1. So you choose to
a.move forward to intercept the motion, or
b. Or you choose to move away to give yourself more reaction time, or
c. You move on an angle away or toward the motion
2, Then both your arms rise
a. creating synergy from the doubling effect of that movement.
b. you shift forward or backward with a rolling motion of your center. This becomes the fuel behind your response.
c. your rising lead hand rises on your centerline then roll out fron there, creating a motion to deflect the attack,
d. your other rising hand enters the opponents body as an uppercut, with a rising motion, then continues to rise with the strike continuing, this creates a rising force from the strike. One that rises toward the opponents throat.
3. As this is occurring your stepping forward with a crescentstepping pattern moves your rear foot before then behind
your opponents lead step (which step the opponent uses
does not matter) effecting a sweeping motion with that step.
4. Throughout the movement you choose to use inhalation to close into your opponent. This inhalation draws your center toward the opponent.
Simply stated a different way, ‘Man starts to strike, Fall down, Go Boom!”
And as I am old and most decrepit I will offer myself as an example of less than perfect which I have devoted myself to attaining.