As someone who is soon to test again for rank, I found my mind returning to the question of why we test at all. This is especially poignant given the general consensus that rank is of no importance. "If advancing in rank doesn't matter, then why test?" the reasoning goes. "If I fail, what have I lost?"
Viewed with a fixation on rank, testing is difficult to justify. But testing is more than a way of acquiring rank (meaningless or not). Testing is a tool for improvement. During the period leading up to the test, we practice harder and more frequently. We are encouraged to focus on specific techniques, and question them in detail. We must become technicians. This kind of training takes us outside of our habitual practice and allows us to see techniques in a different way.
Then there is the test itself. During the test, we must exert ourselves to the utmost; we are pushed harder than any class pushes us; we are mentally and physically exhausted. This kind of training leads to improvement of a different sort. It reveals how we behave under pressure. It reveals how we handle fear. And, with our muscles exhausted, it reveals how to act from our center, from our hara.
Years ago I was told that during the test "you must die on the mat". At the time, I took it to mean that I must try hard and exert myself a great deal. However, there is more to this assertion than I initially understood. Trying hard is one thing, giving everything is another. Giving everything requires us to let go of our fears and desires. It requires us to let go of our very selves. This is the death we must strive for.