Jan de Jong's jujutsu shodan grading includes suwariwaza no kata. This is a kata of five defences where both tori and uke are in seiza. I am currently using suwariwaza no kata as a learning tool.
Suwariwaza no kata is judo's kime no kata, or at least the first five techniques of that kata. This is a fact that was never disclosed within the Jan de Jong Self Defence School, probably because the only person who was aware of it was De Jong himself. When I discovered this fact while studying Jigoro Kano's Kodokan Judo (1986) and brought it to my instructors' attention, (a) it was largely ignored, and (b) it was suggested by some that this was Tsutsumi's contribution to Kano's judo. The latter suggestion, I would suggest, is an example of shoehorning.
The fact that the instructors did not know this kata was judo's kime no kata highlights a paradoxical difference between De Jong and his senior instructors. De Jong was constantly studying other systems and martial arts. He incorporated this research into his own style of jujutsu. His instructors on the other hand did not look without, they only looked within. De Jong was the source of all knowledge. If De Jong made an error, it was passed down religiously.
The not looking without by the instructors is highlighted in that every year the same question would be debated in the instructors class. It remained unresolved at the time of De Jong's death. Which leg do you throw back in the fifth technique when throwing uke? The definitive answer was there all along, however, not once was Kano's book, or any judo reference for that matter, consulted.
An understanding of the biomechancis of balance would also have answered the question. Throwing one leg back reduces tori's base of support to one knee. If the left leg is thrown back while trying to throw uke over the left shoulder, tori's weight has to be transferred over the right knee to remain balanced. This weight transference works against the technique.
There is a question that was never asked, and it should have been. The first technique involves uke holding tori's hands down on their thighs.
We were taught to unbalance uke by sliding the hands off the thighs and pulling slightly to either side of tori's body. 'Divide and conquer' as the unbalancing was referred to when standing and both wrists were grabbed by uke. Tori rises to their knees and kicks uke. Why does tori kick uke? To unbalance uke. But isn't uke unbalanced by the divide-and-conquer unbalancing?
I used to divide tactics into three phases: bodymovement (taisabaki), unbalancing (kuzushi), and technique (waza). This division is based on De Jong's division seen in the mon grades he developed. The use of these terms has proven to be a little confusing, so now I refer to: evasion phase, facilitation phase, and execution phase.
Strikes and kicks are often used to facilitate the execution of a technique. It is often referred to as 'mental unbalancing' as compared to physical unbalancing. If you physically unbalance uke using divide-and-conquer, you don't need to mentally unbalance them with the kick, and vice versa.
We always had trouble getting the kick in after we'd unbalanced uke. The reason we had trouble is because you are not suppose to physically unbalance uke. That simply results in uke leaning forward and obstructing the kick. All those doing this kata in any of the schools teaching De Jong's jujutsu - do not physically unbalance uke when executing this technique.
This highlights an important issue. If you see a strike or kick being used to facilitate the execution of a technique, and you see physical unbalancing method being used as well, ask why. It may be that the strike or kick is being used to facilitate the physical unbalancing, but I cannot think of an instance where physical unbalancing methods are used to facilitate a strike or kick to facilitate the execution of a technique.
It should be noted that aikido teaches a similar technique but uses physical unbalancing rather than a kick to facilitate the execution of the technique. This is more akin to what we do when standing, a defence included in yellow belt.
The second technique is a punch to the stomach which tori evades by raising one knee and pivoting to the side. At the same time they execute a brushing block and a strike. Was an evasive bodymovement used to evade the attack? Yes. It was nagashi taisbaki, or flowing bodymovment. If a bodymovement was used to evade the attack, what is the purpose of the brushing block? This should always be your question when a bodymovement is used to evade an attack and a block is also used. You don't need the block to stop from getting hit or kicked, the bodymovement took care of that. So what is the brushing block used for? The same question can be raised with regards to many standing techniques where a bodymovment is used to evade the attack and a brushing block is also used. What is the purpose of the brushing block?
Our brushing blocks were sometimes referred to as deflection blocks. I asked a student training this technique to explain it to me and he referred to a deflection block - and that is exactly what he used. He was accurate in his description, but inaccurate in actually executing the technique. A deflection changes the direction of a strike or kick. If you've evaded the strike or kick using a bodymovement, why do you then change the direction of the strike, in this case pushing it away from you when you then want to bring it back to apply the stomach-set-arm-breaking technique?
The third technique involves a strike to the forehead and no evasive bodymovement is used. A block is used to change the direction of the strike. We were always taught that it was also to physically unbalance uke. However, a kick is also used to facilitate the execution of the technique. We can immediately see, given the above rule, that their is a problem here. The unbalancing with the hand was always problematic as it physically unbalanced uke backward and then they were brought forward onto their stomach. The answer lies in the fact that the block is not used to unbalance.
You could use the block to unbalance. Aikido does. But then the kick is not used and the technique is usually executed to uke's rear rather than their front, although, it can be executed to their front using a robuse (arm rowing), which is a feature of Mochizuki's Yoseikan aikido. The latter technique and the influence of Mochizuki's teachings on De Jong might possibly explain why the block was thought to be unbalancing uke - but why then use the kick?
To recap, divide tactics into phases. My division is evasion, facilitation, and execution. If a bodymovement is used to evade an attack and a block is also used, ask what the purpose of the block is If a bodymovement is not used to evade an attack, a block has to be used to stop or change the direction of the attack. If both a strike or kick and physical unbalancing methods are used to facilitate the execution of a technique, ask why both methods are used.