According to whom?
The reason why Japanese iron is inferior is because of the source of the iron itself, they utilized iron sand instead of rock ore. Rock ore can be made up to 90% ferrous material while the iron sand contains as little as 2%.
This means when you smelt your source material into blooms of iron and slag, the blooms made from sand iron were much smaller. Instead of utilizing a single bloom to make a sword, the Japanese had to work several blooms together. Which is much more labour intensive, and can lead to a lot of imperfections in the final product.
This is why katanas were made out of so little material, and had to be handled with care. They were much more fragile pieces than similar swords made in Korea and China at the time.
Plus, the Japanese developed their iron working much later than their mainland contemporaries, as they never independently invented furnace technology. The technology for furnaces was imported, most likely from the Korean peninsula.
What century of katana are you speaking about? Many katana were used with modern metallurgy technology and imported steel. Do you think modern Japanese created cars are also made from steel refined from sand? Do you think the guns Japanese Samurai used were made from steel refined from sand?
Lol, my dude. No one is claiming that modern japanese steel is of poor quality.
Im speaking of the time period contemporary with the accusation. You know, how arguments typically work…
Do you think the guns Japanese Samurai used were made from steel refined from sand?
Just pointing out this one because it’s funny. Yes, a lot of the early firearms made in Japan were still made from iron sand (Satetsu). Which was the main source of iron in Japan until the 16th century.
There was nothing inherently low quality about using iron sand anyway. Impurities were carried away by slag and the iron in the sand was easily recovered using washing and later electromagnetism. Imports were used as demand increased.
