The following should not be considered fact :
From what I understand during the time (Edo, Meiji ??) when the Samurai were forbidden to carry swords the kiseru was a substitute weapon, and we're not talking concealed blades here .
Some were quite long, others were normal sized : mine would have filled the fist quite nicely .
Now I know you're thinking to yourself:"Okay, but can it cut a machine gun barrel ?? "
I wonder if there are 'forms' for pipe fighting ...?