Fair question.Lightknight said:Were the swords made of period correct steel and tempering or were they cheap replicas made with newer/cheaper steel and factory temporing?Not G. Ivingname said:The Mythbusters tested various swords, to see if one could cut another. The best they did hit was some swords hard enough to make them snap from bending, but only after making a machine that swung far harder than any human could that was wielding a Scottish Claymore to hit some very thin blades. No, they couldn't snap a Rapier with a Katana.
No human with a sword could slice through another sword, unless said sword is made of rust, glass, or chocolate.
I rewatched the segment (here it is, if you want to watch it: http://dsc.discovery.com/tv-shows/mythbusters/videos/slicing-a-sword.htm). They say all of them are really high end replicas, but it was noted that each of the swords were cast from high carbon steel. They don't say who or how each sword was made, and being made from the same strain of steel means local variation in metal strength won't be a factor (to be fair, Japan's iron supplies were both limited and not of very high quality).
I have looked a bit into history, and the west did have contact with Japan during the Sengoku and Edo periods, originally by the Portuguese (a ship of theirs was blown off course while heading to China). I do know there was some fighting between pirates from both sides and Japan/the European traders, and I haven't found any records of Katanas slicing through the rapiers the Portuguese wielded.