My guess is it's a play on this:

http://i1259.photobucket.com/albums/...ds/image_1.jpg

http://i1259.photobucket.com/albums/...ds/image_2.jpg

Not sure about its significance to Ninjas though.

Video walkthrough of the event, including better look at some stuff.

https://www.youtube.com/watch?v=nbYTJbZUUZM

That background music when transform, such beautiful

Wow, they actually sold the ninja gear they wore in the promo? Nice.
The guy says that for one of the freebies, Kyoryuger gave out jyudenchis, for ToQger they gave out resshas, but this year all they got was a hologram sheet with a QR code on the back where they make you sign up to get the ninshuriken.

Actually i think it is more of this.

http://omatsurimuseum.net/images/038.jpg

It's called a koshi in Japan.

If all the Ninninger fights are like this I may have a new favorite series. :D

Haha this absolutely great :lol

WTF he's hiding inside the building that's crazy awesome! :D

That's the first thing I've seen that's pumped me up for the series. That's awesome :lol

Since when Japan have that kind of building? It's like they built it exclusive for mecha battles, haha :D