Getting back into old habits, I see.

Those swords are so bloody long they must weight at least 2.5 kg. Makes me wonder if it isn't the swords swinging Shinobu, in fact.

Kraco said:
Those swords are so bloody long they must weight at least 2.5 kg. Makes me wonder if it isn't the swords swinging Shinobu, in fact.

I believe those are nodachi (http://en.wikipedia.org/wiki/Nodachi), but I can't be sure.

To find it out, one need to read the Kizumonogatari (3rd novel from the Monogatari series), or just wait it being animated on 2012.