What is the difference between Ninpo, Ninjutsu and Bujinkan?
I will try to be as clear as I can. In the way of speaking there is not (much) a difference. As you will read on this homepage, the bujinkan exists of 9 traditional schools. The 9 Ryu. They are Ninja and Samurai schools. Only three of them are really Ninjutsu schools. The others are Samurai scools. The name of the orginazation is “The Bujinkan.” The word that is mostly used when you are a member of the bujinkan is probably Ninjutsu. Ninjutsu is what you train and Ninpo is seen as the highest order of Ninjutsu. So when you use your skills, you learned from Ninjutsu, in real situations that you can call that Ninpo. I hope I explained this correctly otherwise send me an Email.
Bujinkan is the modern mix of 9 ryu ha. The Bujinkan has 3 Ninja schools in its curriculum, the rest is Samurai Ju Jutsu. When you practise Bujinkan you learn the concepts of the different schools as main thing.
So when you practise Bujinkan, you practise Bujinkan with elements of ninjutsu.
The other faction of Ninjutsu from the Tanaka clan was a pure Ninjutsu school. So not 9 ryu ha combined The Koga Yamabushi Ninjutsu school was passed on to Hanshi Frank Dux by his teacher Shidoshi Senzo Tanaka. Senzo Tanaka was also known as Takizo Tanaka and was also a master of the Yagyu Shin Kage Ryu.
Also the Koga Yamabushi ryu Ninjutsu is not pure ninjutsu anymore, because Frank Dux created his own style called Dux Ryu Ninjitsu