This is now a multi-part series. You can find
The final movement in each shikodachi step is a two-handed, open-handed soto uke followed by a slow retraction with the lead hand to the hip that is paired with a palm-up nukite to the front (not across the body as is done in a number of other schools). I have been shown two basic interpretations for the technique. The first is an interception-catch-armbar of an incoming attack or grab attempt and is to the outside of the opponent and the second is similar in that it clears a grabbing arm/attack (to the outside as well) and then strikes into the exposed ribcage.
The armbar technique is essentially a chin-na technique that extends and locks out the elbow, with the rear hand intercepting the attack, the lead hand coming through to clear and extend the arm, and the rear hand then applying outwards and upwards pressure (the "nukite") to the triceps tendon and providing a fulcrum for the lead hand to work against. It is very similar to the reverse-punch application in saifa, and similar chin-na style applications appear all through the various kata.
The technique can also be used against a same-side lapel grab to wrap the arm and take the attacker down forwards - the angled shift rotates the attacker away a bit from me, and puts a bend in their arm, allowing the lead hand to wrap under and around their arm, putting it into an arm lock, and bending them forward. The rear hand then represents a strike to their exposed ribcage or head.
Part of my thinking on this movement is to do with how it transitions into the next movement - and there are two. The first subsequent movement (if that makes sense) is to step across at 45 degrees on the opposite angle and repeat the whole sequence again. With the trapping movements, that works very well as a way of throwing the attacker to the ground by trapping the legs and shifting bodyweight through their angle of weakness.
The other transition is into the terminal part of Section A - from shikodachi into zenkutsudachi, with the right fist nestled in the left hand. Generally, touching one part of the body with the open hand can be thought of as indicating that the body part is being grasped by an opponent (and indeed, my understanding of the terminal section of Part A is predicated on just this supposition). I am struggling to see how the two trapping techniques can transition easily to this position as anything worth grabbing is in the wrong position as a result of the previous technique.
It is entirely possible that there is no transitional technique between the end of the shikodachi step to the terminal part and it should stand on its own. Without someone to practise on, that is my (temporary) conclusion on how to treat it. I should say (I don't think I have before) that of the techniques I am putting forward I have learned/been taught about 1/3 of them. The remainder I have either seen or learned as techniques in isolation and have reverse-applied them to seienchin, or have worked out (made up !?!) from first principles. I have, however, tried all of them out before writing them down, and they work sufficiently well for me to commit them to paper (or its digital equivalent). However, your mileage may vary considerably.
So, the terminal section of seienchin is from zenkutsu-dachi, with the hands bowed horizontally in front of the body, right fist in left hand. Then, the body and front foot withdraw, the hands rotate to the vertical, and then as the body pushes forward again, punch (left hand stays covering right wrist). The front leg steps back, weight goes on to it as the right hand retracts and left extends, open, outwards. Then, weight shifts forward and vertical right elbow (with kiai).
At a superficial level, this segment begins with a wrist grab which is covered/pinned by the left hand. Before they can punch, they are quickly pulled off-balance (the little backwards flick of the right leg as it moves back can be interpreted as an implied low-kick to help with the off-balancing), then the grip is broken by the rotating fist which then finishes by hitting them in the solar-plexus. By itself, the step-back-elbow section is an alternate way to deal with the wrist grab by shifting more backwards to pull them forward, clearing the grip with the left hand and hikite of the right. As they stumble forward, the elbow smashes them in the face, left hand coming behind their head to control it. These two moves can be easily strung together in a single flow as well.
By itself, the first part of this segment is directly translatable to a nikajo wristlock, where the open hand is pinning the opponent's grip.
On a tangent, I find it interesting that when parts of a kata that deal with grabs are asymmetrical, they are pretty much only on the right hand side (as is the case here). Apart from the general right-handedness of the majority of the population, is this because most people would hold a weapon in their right hand, and hence have it grabbed to control it? I have no idea, but it's an interesting thought as to how techniques would work if they were being used to free a weapon-wielding hand. I have had nikajo and shihonage taught to me in aikido from the point of view of having a weapon hand immobilised, but to this day I do not know if that was to highlight certain mechanics of the technique or to show a possible point of origin for the technique. I wonder how this part of seinchin would work if I had a knife in my hand? (possibly not too well; the rotation of the right hand in relation to the left seems to close to vital nerves and arteries for my liking). Still, it's fun to think about occasionally, even if it's mostly likely not the intent of the kata.
Part 5 will be looking at Section B.