Hattori Hanzo was no swordsmith but a Samurai / Ninja at the end of the 16th century (from 1542 until 1596)

I think you are talking about Muramasa and Masamune who dit exist and did create swords that seem to keep well in time.

I suppose you are talking about the Kill Bill version but have to ask what exactly do you mean? Is it his personality? Or how the swords are forged? Or the fact he owns a Sushi shop?