Moving discussion in general martial arts to here:
Would the practice of sanchin help those who study taekwondo, in your opinion? If so, in what way? Has sanchin practice help to develop your aikido? If so, in what way?
It teaches correct posture and framing for maximum structural strength and stability both when moving and standing still. There are certain underlying assumptions that go hand in hand with this that Sanchin also teaches, such as unity of body and using your breath to augment your structure.
The kata doesn't look like much outwardly to laypeople but there's a lot going on there. Now certainly different arts create structure and power by emphasizing different qualities. The way Goju-ryu does it comes directly out of lengthy Sanchin practice, and it's unmistakable when you look at a karate-ka and you know what signs to look for.
I usually start teaching Sanchin to new students within the first few weeks, but it takes years to develop proficiency in. From some accounts, Master MIYAGI Chojun kept his students working on basics and hojo undo for a few years before teaching them Sanchin. And then he kept them on Sanchin for another 3+ years before teaching anything else. While very conservative by today's standards, this methodology underscores how important the kata is within the system.
Would the practice of sanchin help those who study taekwondo, in your opinion? If so, in what way? Has sanchin practice help to develop your aikido? If so, in what way?