Sooo many idiots.
Why do you guys even bother posting if you don't know about martial arts? Just shut up, you'll look smarter..
There are 3 'grand masters' of ninjutsu. One is Hatsumi Masaaki, another is Tanemura Shoto, the other is Manaka Unsui.
All eventually trace their skills to 1 person named Takamatsu Toshitsugu who passed various ryu to his students.
Hatsumi heads the Bujinkan which is a large organization teaching 9 ryu, with about 5 of them being strongly linked to ninja of the Iga province in Japan.
Tanemura heads the Genbukan and teaches a large number of ryu, as he holds many menkyo kaiden or 'masterships'. He also teaches ninja ryu as well as standard samurai ryu techniques (such as asayama ichiden, and hontai yoshin takagi)
Then there is Manaka, I don't know much about him but he tends to focus more on the 'samurai' side and trains very heavily in the basics. His school is called Jinenkan. He teaches one ninja ryu ha which is of course Togakure ryu. However it is not as prevelant in Jinenkan as it is in the other "kans".
Spinning a sword over your head is a sure way to chop your fingers off. I don't know of any kenjutsu ryu that have techniques in which a sword is spun in the manner that a bo is spun. If indeed one ever existed, its founders probably killed themselves trying the techniques.
Generally the only time the sword is held above or at head level is in a kamae (posture) called daijodan or jodan no kamae. There's no other reason to have the sword up there except for a last resort blocking maneuver..
Some samurai were ninja and therefore you can conclude some ninja lived by the code of bushido.
However I strongly doubt that most members of Iga and Koga province families followed bushido, as ninpo is far more logical and to be honest, successful. People of modern day societies rely on many of the principles found in ninpo. Almost no one relies on the principles found in bushido- though the ones that do are very notable.
Samurai are not all they're cracked up to be. There are many cases of bad samurai, samurai who kill their lords, and all kinds of other treachury. Be real- these were human beings subject to life/death decisions all the time. They did what they needed to, and tried to live by bushido if they could. The stone headed ones did everything for honor. The smarter ones just did whatever it took to win.
As far as the word Grandmaster is concerned, you sound like you have crawled from an Ashida Kim book, so I'm just going to say everything you have written is wrong. The word Grandmaster is roughly translated to "Souke" in Japanese which means "head of the family". This word has been used for centuries to describe the person who has inherited ALL techniques from a ryu from the previous grandmaster. It also means he can do ANYTHING he wants with the ryu, including disband them, add things to them, removing this from them- ANYTHING HE WANTS.
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IMPORTANT
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Ninja have nothing to do with Sun Tzu and the Art Of War. This garbage is taught by a man proven to be a fraud under the alias Ashida Kim, real name Cristopher Hunter.
Some ryu (schools of techniques) evolved from Chinese arts very long ago, such as Gyokko ryu as far back as 1000-1100AD. However from that point on they are strictly Japanese. Strategy matters sometimes have similarities to the Art of War, however sticking closely to the methods of that book would destroy the purpose of having ninjutsu wouldn't it? The idea is to be unconventional, not the same as everyone else.
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By the way, I am a member of the Genbukan, previously I was in the Bujinkan. There are numerous ancient texts (written in Japanese) that depict various elements of ninjutsu, which verify the authenticity of the art in its present form. If you're that interested, ninpo.org is a good place to start.
Now please stop being idiotic, and research before you post. You could have learned everything mentioned in my post with 30 seconds of googling.
Thank you.