Think about it. They both have names, they both have strange powers, and they're both empathic weapons with minds of their own. In fact, Tenseiga's Meido Zangetsuha is very similar in appearance to Ichigo Kurosaki's Getsuga Tensho, which is fired from his blade, Zangetsu. Furthermore, at one point Inuyasha has to battle the Tessaiga to gain one of its abilities, which is very similar to how Ichigo had to battle Zangetsu to achieve Bankai. Lastly, Tessaiga's Wind Scar and Ichigo's Getsuga Tensho are both attacks in the form of a massive wave of energy fired from the blade.