I think it's more that it's a deeply personal journey, beginning with those first steps into a dojo, learning first to master your body and it's strengths, weaknesses, limitations and potentials, then moving onto taking control of your emotions, through experiencing mushin and zanshin states, and eventually then moving onto aspects of spiritual development by understanding your own mortality through the techniques and training you are exposed to. The most obvious form of this is of course the sakki test, as in it you are (supposed to be) facing your own mortality, throwing away your life in a moment of faith in your own ability to naturally evade, with your deeper survival instincts taking over. At this point, there is no way to describe how you do it, if there is, then you have missed the point. And that's the beginning.
As you progress, every action takes on such profound learning potential. This is echoed in the prayer/affirmation from Kumogakure Ryu spoken at the beginning of most classes, and often at the end as well: Shikin Haramitsu Dai Komyo (loosely translated, within every action there exists the potential to find teh enlightenment we seek). In all martial arts, this experience exists, but the exact way it is found is individual. Takamatsu Sensei became very ill, and went into the mountains. In his moments where he didn't know if he would live (in fact, he believed he would definately die), it allowed his mind to be more aware, and that was his satori moment. Hatsumi Sensei has said that he gained satori in the mountains of the city, what the Westerners sometimes call the concrete jungle.
The origins of such thoughts and principles (at least in Togakure Ryu) seem to come from Daisuke Nishina (Daisuke Togakure)'s early training and education in the Shugendo of Togakure Yama, where the practitioners face their mortality in each and every training device, including things like fire walking, and hanging by one hand off a cliff for long periods of time. By constantly exposing yourself to danger and potential death, your awareness becomes heightened, and that leads to enlightenment/satori.
One last word on enlightenment. It is not what most think it is. Most people tend to have the impression that enlightenment is passive, peaceful, a very positive and loving way to look at the world, and that is not it. Enlightenment is just like the word says, everything is lightened. In other words, you begin to see the world the way it is, without the veil of your personal worldview, or the limitations that society places upon you. And that can make you very angry. Persons such as Jesus of Nazareth, Moses, the Prophet Mohammed, Ghandi, and others are very good examples of just that idea. Although many think of them as being loving and peaceful, they were for the most part frustrated and angry at the way the rest of the world was behaving, leading to their actions in each case.
Oh, and one last thing. The term "esoteric" refers to particular knowledge only gained after certain requirements are met, it is something held back for only a few. So not many will happily just "give it away" on a forum, not even me. This has all been deliberately vague in details.
Hope that makes some sense to you!
