Japan's iron and steel is so scarce, why the Japanese sword belongs to the world's famous sword

Japan is not an iron poor country, and Japan's unique jade steel smelting method to create a sword performance is also very good, I have seen a Kovu forging the destructive test of the ancient sword, even if the skin iron breaks the core iron is still coupled, and the grinding of the Japanese sword is also extremely elaborate, a good sword from smelting to grinding, and finally handed over to the hands of the utility, condensed a lot of people's efforts. And the Tang sword is not the ancestor of the Japanese sword, because in the Tang sword appeared before the appearance of the Japanese sword, now no one can determine the origin of the Japanese sword, can be said to be the Han ring head, can be said to be the Turkic sword, can be said to be shrimp razor knife, can be said to be the Japanese native knife, there are many opinions, and the modern Tang sword is not the Tang sword, the real Tang sword is the information on the four systems of the knife, the modern so-called " Tang sword" is basically a copy of the unknown origin of the sword of the Shosoin.