Like how Ryuunosuke from Shaman King got his new Bokuto, Souchou must havc carved her bouken from the Tree of Dragons (KiRyuu).
Um acschually! If Kiryu were to be written with the symbol for dragon, which by my mobile-limited google-fu it isn't, it'd mean tree dragon - as in a dragon of trees - because in Japanese adjectives come before verbs, just like in English.