Lately I've been working more and more on some of the more basic principles of the style that I see many advanced students don't get. Specifically I've been troubled at watching folks do advanced kata and noting how the energy in their thrusts and kicks aren't coming from the core. Oye vey! That's something they should have picked up at least by shodan.
So sometimes you need to take the principles out of the box, and apply them elsewhere. After spending a good deal of time doing Sanching "jar" training with dumbbells (a pretty easy and neat way to cheat on a classic training process), I decided to take the principles to "knee walking" on the mats. If you want to know what this is and see someone who is pretty good at it, check this.
I have a slight variation on it (close to what this guy is doing) where my ankles are as far apart as the feet would be in Sanchin. Why? Well for one, it makes it easy to forward or back roll right from this position, thereby increasing the movement options. Secondly, note how easily this guy stands up, and yet he comes up in musubi dachin. Do a slight variation in foot placement (you'll see him occasionally be there), and you spin 180 degrees right into a Sanchin.
Anyhow... note how well this person moves forwards, backwards, pivots (magate), turns (mawate), and can maneuver off of a line of attack (tai sabaki or tenshin). While the level is different, all principles are the same. Posture is the same too. Note how well this person keeps his Sanchin posture (erect spine, pelvic tuck, etc.). Also note how little "English" is needed with his arms to move.
When I learned aikido, all my techniques had to work at this level. And there's no reason why one can't do a complete Sanchin kata with this movement. Add in a few rolls to embellish and expand on the foundation. This guy throws in some forward rolls...
Warmup Exercises: Shikko (Knee Walking) & Rolling by Gregory Soon
... but if your feet are farther apart (as in Sanchin), you can backwards roll just as easily.
Stand up and twist back down again, etc., etc. Suddenly you really don't know know or care about what level you are using to execute your movement. And you become much more conscious of the large muscles used to keep the core moving.
Think it's easy? Try it.