id say the Nihontou, Japanese sword. Its not perfect, as everyone seems to think, they did break, and chip and so on, but no where else on earth, was the making of the sword as revered as it is in Japan. The sword was one of the sacred symbols of the Shinto Religion, and considered an extremely important part of the religion because it was made using the five elements.
Swordsmiths were on a constant path to always improve on the sword, compared to the smiths that came before them. "The edge is the endless skill of the inventor" as was said by Kazuo Koike, through the pages of Lone Wolf and Cub.
Smiths gaurded there work with fierce energy. Theres a legend that the smith Masamune once had a fellow smith visit while he was making a sword. Even then he was renowned as one of the best swordsmiths in Japan, and while visiting the fellow smith dipped his finger into the water that Masamune used to temper his blades. He had attempted to break Masamune's secrets and understand why his blades were so much better than his own, and without a second thought, Masamune took the redhot, unfinished blade, and struck the offending smiths hand from his body.
I have a book, its called the Connoisseur's book of Japanese Swords. It gives an indepth view at the various shapes and types of NIhontou through Japan's History, including indepth looks at various schools and smiths. This list, includes some 5000 various smiths, and is largely an incomplete listing.
1500 years, of endless improvements and skillful manipulation of steel, forged in a fire of war and battle, and quenched in the water of rebirth, the Japanese Sword is amongst the finest weapons, ever created by human hands.
