I understand that a large difference is that European smiths typically worked with material containing raw iron ore, whereas the vast majority of iron in Japan is primarily found in the form of iron sand as opposed to ore.
I've heard countless times that Japanese iron/steel was fundamentally "worse" than the European counterpart.
Was this a result of iron sand being that much more difficult to successfully process than iron ore, or was there something inherent in the raw material that caused the outcome?
My other suspicion is that the Japanese-style forge (tatara) made it difficult to create high-quality steel in large amounts, with good steel only forming on the outer edge where it was able to sufficiently oxidize. As iron sands are far more labor intensive to mine and collect in the quantities required to feed the tatara, this would make the "good" steel incredibly valuable as such little raw material actually becomes usable steel.
Is this completely wrong or is this on the right track?
I apologize if this question seems all over the place and includes a bit of my own guessing. Ultimately I'm looking for a solid explanation as to what made Japanese steel/iron so ubiquitously "inferior" that it required such advanced techniques just to create a usable product.
It is true that iron sands, used to make Japanese arms, are impure, especially if you compare them to the average European ores of the same time (Although in earlier periods, bog iron was sometimes used which is impure itself). However, when the iron sands have been turned into tamahagane, the best steels are quite good, with a consistent and high carbon content. Also, the hardness of the different steel types in a Japanese sword has less to do with sword quality than it does the hardening process. The differential hardening creates the hard edge and soft spine, not the quality of the steel. You are correct that the process of converting iron sands into a sword is labor intensive, but the final product does contain good quality steel, if, at least, we take good quality historical swords- like any other culture, Japanese swords could vary from lousy to excellent. I don't think it could be argued that the reason good steel is valuable is because it is rare- it would be valuable because the process of turning iron sands into tamahagane is difficult and lengthy.
It could be concluded that Japanese iron, with its naturally occurring impurities, is worse- or at least more impure- than European iron. However, the steels could be comparable in quality, although with the Japanese method lengthier and more difficult. In the end, these processes both are able to produce good quality swords, with different properties: European swords typically use monosteel and a temper that results in a flexible blade. Japanese swords typically use a laminated steel that has a hard edge for cutting and a soft spine for absorbing shock. The Japanese sword, if bent, will not return true. The Japanese sword will also have a slightly sharper edge (Whether or not this is significant is debated, but it is a slight difference), which has nothing to do with the quality of the steel, but the type of hardening.