It's really quite easy. If you can read kanbun, just pick up the extant primary scrolls and books about ninjutsu. Pretty easy to do a Japanese search for the source materials and where they are kept(National Diet Library, etc). Kacem Zoughari's book also has an extensive bibliography. However, secrets were kept secret by not writing about them or writing in a way that only people with certain other knowledge could read them. Beyond that, there are a few academics in Japan who are researching ninjutsu in this way. Correspond with them and you might be able to get some insights.
ok thanks, I do not know who Kacem Zoughari is so I'll check into him. Are there any particular NDL sources you know of that would be a good start? Quite frankly I could use a few pointers/leads on this subject which was why I first posted, you seemed like somebody who knew your stuff.
I think the problem you'll find researching these things academically, is that without actually belonging to a Koryu system, you will never learn it's 'secrets' - it doesn't matter how much you understand the country's history, what languages you can read, etc But this isn't because of a shrouded in secrecy type of scenario. It basically comes down (as has been mentioned before) to the simple fact that lots isn't written down anywhere, so there's nothing to research. Kuden are passed from teacher to student, and survive in that way. Even where things are written down (again as mentioned before) they are often written in a way that doesn't give too much away. For example 'Grab their arm' tells you in part what to do, but how should you grab it? that needs to be taught, you see this time and time again, that's why people can't learn these arts from books no matter how hard they try. So searching for 'secrets' wont turn up much - and you'll also find that what's 'secret' in one school, is taught openly in another, but they then have other 'secrets' Yes things are more open than say 50 years ago, but that doesn't mean in any way that every school has laid everything on the table for the world to view with no actual commitment to the school. No matter how open things become, there will always be things held back, even from most senior students in lots of cases, and only passed to a select few, and they've had to put so much into gaining that knowledge, they're unlikely to openly share it with the world.
If you can read Japanese, it's easy enough to google ninja books. That will give you sources of published works(although it's been posted here before too). Problem is that there isn't much to go on. Accounts of battles where ninja were actually active are hardly good detailed sources of their tactics and strategies. Many books plagiarized things from Chinese sources and elsewhere without necessarily testing the things written down, and the issues Kobudo raised are also important to keep in mind. As there are basically no real academic works on ninjutsu in Japanese, you are pretty much stuck with trying to collect and decipher things on your own. Not that it isn't worth it, but it's not easy without some kind of understanding of what you're looking for anyway. Good luck.
