Chris Parker
Grandmaster
I could agree to an extant on Ninjutsu being a Japanese martial art, with a Japanese kanji name, using mainland Asian strategies adapted to mainland Japanese cultures and traditions. But the core of Ninjutsu is still Chinese in nature. In ancient Japan, such guerilla warfare was shunned by the Japanese who viewed it as dishonorable and cowardly. But in ancient China, deception was the key to all warfare. They didn't concern themselves so much with valour and justice. They had a more realistic view of warfare and how to win using any means necessary. So in many ways, the Ninja are more Chinese than Japanese.
Dude. Stop now. You're just wrong. Deception was just as much a part of Japanese warfare, combative methods, and so on as it was anywhere else. Ninjutsu is purely Japanese, and thoroughly Japanese in it's methodology, culture, and so forth.
Seriously, this is completely wrong in everything you're saying. Up to and including the idea that "ninja" were guerrilla warriors....