lso do you have any position on the possibility of stealth armor for ninjas?
The Japanese were the largest producers of armor in the world, from very early times right up until the end of the samurai era (1868) and even beyond that. They made an incredible variety of armored clothing and many with the armor defense hidden from view. This included armored pants, vests, shirts, jackets, sleeves, gloves, hoods, foot coverings, and belts. I could not imagine anyone in feudal Japan who was in fear of armed conflict not wearing some sort of armor even if it was just a layer of kusari (chain armor) sewn to a common clothing article. Until very recently images of this type of armor were hard to find but now there is enough evidence to suggest that wearing armored clothing was very common. I can show you period prints that clearly show samurai wearing armored clothing, you just have to know what to look for.
Since for the most part ninja would have to blend into the crowd, wearing traditional armor was not an option, wearing hidden armored clothing is what I would expect ninja to have worn, light weight armored sleeves and a vest, shirt or jacket with a kusari, karuta or kikko lining, these would be undetectable to the average person and would have provided a measure of extra protection both physically and psychologically.