We all know that there are 4 classes of Meito. Supreme Grade Swords (最上大業物), Great Grade Swords (大業物), Skillful Grade Swords (良業物) and Grade Swords (業物). according to this wiki, Sandai Kitetsu is one of grade swords (class 4th). but when I read manga in English, it said skillful grade (class 3rd). I can't find the original version in Japanese.
So ... what exactly grade does Sandai belong?