Ken tai ichi no kata (form of sword and body as one) is a kata that is designed to illustrate the similarities between sword and unarmed defences. The lesson is far more complete if the similarities and differences between sword and unarmed defences are identified through the kata.
It's not just the similarities and differences between the sword and unarmed defences that produce the lessons in ken tai ichi no that produces the knowledge, its also the identification of similarities and differences between the different defences in each class of defence.
For instance, what are the similarities and differences between the kamae (combat engagement position) of each of the sword defences? One is seigan kamae which is a totally defensive position where the tip of the blade is pointed at the opponent's throat or eyes whereas the other four are not. Tactically, this means that the attack in the case of the seigan kamae involves either moving around the sword or moving the sword off the line of attack. With all the other kamae, the attack can be straight down the line. A tacical lesson is learnt through the identification of similarities and differences between the different kamae adopted by the defender.
One difference between the armed and unarmed versions of this kata that is emphasised in Shihan Jan de Jong's adoption of the kata is the use of unbalancing techniques/tactics with the unarmed defences which is not possible with the armed versions. Some of the senior instructors at the Jan de Jong Self Defence School attempted to 'shoe-horn' an explanation in suggesting that the 'brushing blocks' with the sword would slightly unbalance the opponent forward. A basic understanding of biomechanics dispels that shoe-horned explanation.
This lesson is then capable of being applied to other arenas. There are aikido schools that adopt the same position, including the hand position, as holding a sword when unarmed. Why would you position your hands as if holding a sword when you are not holding a sword, a hard, metal, sharp, pointy weapon with an extended reach? This then leads to questions regarding what Donn Dreager referred to as the difference between the focus on self-protection (jutsu forms) and self-perfection (do forms).
Extending this lesson further, why would you adopt the fighting style of an animal when you are not that animal and do not possess their weapons. Drunken monkey or sober monkey - monkey's cannot form a fist. The human ape is the only ape capable of forming a fist due to the evolution of their fingers which were no longer needed for climbing trees. A study that I've referred to before explains how the human hand evolved in order to support prehension and percussion applications. It is one of the things that set us apart from the other apes and put us at the top of the food chain. Why lose that combative advantage for a theoretical principle?
One of de Jong's pet peeves was those martial arts that fashion themselves after animal forms. If you're training a tiger style martial art, as many do, are you going to take an opponent to the ground by biting their rump?
