You, as a Master Mason, should seek more light, in your efforts to become a better man.
As a Martial Arts practitioner, you should always be seeking that same enlightenment.
In both, we are taught to seek balance.
This pin provides a reminder of both principles, remembering it is up to each of us to be the best at what we do, to reflect upon our thoughts, and actions in such a way as to glean personal insight, and control.
Sensei means teacher, or instructor. Whether directly, or indirectly, people look to you to set the standard, to lead by example.
Be a good example.