Soo Mukaiji: New Video
Approaching A work Like Soo Mukaiji
The difficulty of a work like Soo Mukaiji is not the Mukaiji part, its the Soo part. Read about that below the video.
Shawn Renzoh Head records Soo Mukaiji with gongs reverberating.
This work comes from the Shimpo-ryu school and has a specific meaning to the word soo. The original Myoan school of the Edo period became known as Myoan Shimpo-ryu, headed by Katsuura Shozan, the last head of the school.
In classical Japanese culture there are a trio of terms used to divide various subjects up into degrees of formalities referred to as Shingyōsō (真行草). This is a concept that can be found in everything from the categorization of utensils found in Sadō, to the types of brush strokes in Shodo.
“Shin 真 is a more recent form of the older 眞 with the same meaning. in turn, this character is made up of the radicals “saji” (utensil;匕) and an abbreviated form  of “kanae” (tripod kettle/cauldron; 鼎). This infers the action of filling a vessel by ladling things into it; to give truth; essence (that which is flawless, not lacking nor wanting; comparable with 実) and thus reality without delusion.
Gyō: The Shell and Bones script of “gyō” or “okonau” (Rajas; 行) is a pictograph of straight and crossing roads expressing going, movement, progress; a journey. Later it comes to express the quality of conduct; how to do something; performance (carrying out an action).
Sō: Also read as “kusa” (grass; 草) is made up of the phonetically derived  “haya” (early; 早 – though its own etymology is derived from “ashita” (morning, “turning of the moon“; 朝)), and the radical on top is a more recent iteration of “kusa” (grass; 艸). These combined expresses the rising of the sun through the life of a plant, both expressing lowliness of grass, also the rising of expression with the sun; often used to express abstraction in aesthetics.
The engaging distance is large (far): To-ma (遠間)
The way of moving is the same as in kumidachi: Futsu Ashi (普通足), which is normal or regular walking (lit. normal feet/steps)
In Kiri-otoshi, the cut in Shin is directed to the solar plexus, Suigetsu (水月).
The engaging distance is medium: Chu-ma (近間)
The way of moving is faster: Haya Ashi (早足), fast steps
In Kiri-otoshi, the cut in Gyo is directed to the throat, Nodo (喉)
The engaging distance is small (near): Chika-ma (近間)
The way of moving is fast with very little steps: Kake Komi (駆け込み), which, although translated as rushing, still allows
control of the movements.
In Kiri-otoshi, the cut in So is directed to the head, Men (面)
Though the expression of Shingyōsō appeared to have maintained a fairly straightforward meaning through it’s progression in asia. However, when it was incorporated into the martial arts, it appears to have taken on several directions of usage; regardless of the particulars, it has always shown to be used as a measure of “Ideal” (shin; 真), “divergence” (gyō; 行), and “freedom” of expression (sō; 草) – a system of “appropriateness”.”