There may be something to be said for measuring student hand size using Small Intestine 1, Triple Warmer 1 or Heart 9 instead of or in addition to Pericardium 9. There is the challenge that many students cannot really communicate that the ruler feels good or awful. I am largely responsible for going an extra distance to make their rulers somewhat more customized than one provides with neurotypical students. With most people, cybernetics works well - it something hurts, they stop. Most bodies like qi, so if the ruler is being used correctly the feedback encourages people to keep practicing. And they make adjustments as needed. But with the bulk of people along the autism spectrum none of that works. So I have a duty to train them in sensations of the ruler being level, the shoulders, hands and feet being positioned correctly and so on. There are photos of rulers compared to a horse blocking knife in the weapons section for that particular blade - they are NOT included here as I have come to the conclusion that the horse blocking knife is probably not built correctly.