Kuden (verbal instructions) are important and universal enough to span centuries and cultures; every art, profession, and avocation has them. Unfortunately, though, these gems of simplicity tend to be ignored and forgotten once they've done their jobs. If you are in a position to teach or mentor, you've no doubt already come to appreciate these nuggets of wisdom; if you aren't (yet), still don't be too quick to discard kuden. Like any true friend, it's not just that they are/were there for you when you needed them; the memory of them can provide strength and guidance when there's no one around*.
To use a common modern example, take something as simple as 'look both ways before you cross the street,' a phrase so ubiquitous that it may be hard to remember the first time someone said it to you. Chances are that the introduction came from someone senior to us (a parent, guardian, older sibling or teacher); though it comprises words that we know, the phrase probably didn't mean very much because we lacked the practical experience of why people slow down when approaching an intersection. After a while, it sinks in that this idea is rooted in experience and that it isn't just some arbitrary suggestion, but a legitimate tool, and that looking out for one's safety is a shared responsibility (we can't expect that motorists and bicyclists will always be aware of pedestrians.)
Once we're old enough to start traveling without supervision, there may be an occasional flash of memory of someone saying, "look both ways before you cross the street," but in large part, you don't have to think about it. That kuden has served its purpose and expands to controlling vehicles as well. So, if a phrase as simple as 'look both ways' can inform your decisions, not just as a pedestrian, but as a bicyclist and driver, what untold fount of magic powers are contained in the kuden of something older and/or more esoteric?
Without going out on too much of a limb most are pretty mundane, detailing things like which "foot initiates a turn." The simplest aim is creating and maintaining consistency in (at first, exclusively) physical mechanics. Once those kuden have done their jobs, something interesting happens. Beyond the obvious detailing of foot placement, there are core alignments suggested (maintaining 'directional agreement' between toes and knees, which strongly implies how to position hips, center, trunk etc.). Somewhere in the process of manifesting these principles, Kuden become a part of how you inhabit and move through physical space. It is notable that a 'turn' of phrase so simple can help integrate a body method, especially one that proves key to everything from 'doing techniques', to power generation, use of weapons and even manual therapy/bodywork... not too bad for five words.**
Yours in appreciation,
Jigme Chobang Daniels, instructor
Aoi Koyamakan Dojo
*More than just convenient mnemonics, skillfully crafted kuden cue appropriate responses from us when there is no teacher or senior whence to solicit assistance.
**Often, the original renderings (in Japanese) can interesting/telling in their own right.