Huh, really? Weiiiiiiiiird stuff. I would have thought with it being crafted from a broken wooden sword it would have been a 木刀 (Bokken) or 竹刀 (Shinai) or whatnot. Learn something new every day!
Edit: Hm, actually, could it be a reference to Shoto, the short Shinai used in nito kendo training and competitions? It's the smaller sword
these two guys are using. Shoto / Shoutou is written in Kanji as 小刀.
(As an aside: Holy cow, there are different styles of Kendo? I thought it was all two hands on one big shinai and swing a thousand times straight up and down. Anime has liiiied to me!)
A quick google search shows 小刀 as "knife" is definitely a much more common use of the word, though.
