I had a good read through http://www.martialartsplanet.com/forums/showthread.php?t=35518&page=7&pp=15&highlight=ninja+15th+dan and did a few searches through the ninjutsu forum but didn't really find a good thread answering a couple of questions I have. Encouraged by post #93, I'd like to start a new thread. Granted, I am an outsider looking in but I just interested in a better general understanding of how things work in this style. Looking at sites like http://www.jigokudojo.com/faqs.htm#rank and http://www.bujinkansf.org/faq/#ranks , I have a few questions in general if no one minds answering them. What considerations are taken in for promotion to a high rank like the 11th-15th dans? What is the average length of time for progression to 5th dan, to 10th dan, and through the 11-15 dan ranks? Also, do the "earth, water, fire, wind, and void" in the 11th through 15th dan ranks have any particular meanings as far as expectations physically and/or mentally... what, if any, is the significance in the use of those terms? Thanks!