The only thing I know (sorry if it has been said earlier) is that every Samurai was required to go into battle expecting, nay, looking to die. It was the highest honour to die in battle. The thought was that a soldier expecting to live would fight worse.
I got that from the ‘History’ section of Age of Kings, so it could easily be wrong.
The fencer vs the samurai (or knight)
In order to understand the evolution of the rapier as the ultimate sword (at least so far) you have to look at thing in the big picture.
In the time of the viking sword and the katana people (well, rich people) wore armor and this provided a fair amount of protection. The firearm changed this. Armor became a disadvantage. So the armor went poof. Now, with armor gone a lighter, quicker sword could easily vanquish somebody using a heavy, slower sword (this isn’t to say that the viking sword or katana are slow, but compared to a rapier thrust they may as well be standing still).
So, a fencer vs an armored samurai. Goodbye fencer. The rapier was never designed to penetrate armor. Unless he gets a very lucky hit he simply stands no chance.
A fencer vs an unarmored samurai. Well, in a duel there is always the chance of death but modern day fencing takes place a ranges far greater then would be typical for the poor samurai. He would simply be outclassed by centuries of martial study that went into the rapier and that type of swordsmanship.
Speaker for the Dead: Nope, pretty darn accurate, except I wouldn’t say they sought death (it is established in the Bushido that dying needlessly is a disloyalty to your lord, I can’t find the quote).
From the Bushido, concerning deathin battle:
There is another quote that I haven’t been able to find, talking about the four plagues of the warrior. Maybe it is the “Book of Five Rings”. Anyway, one of them is cowardice. You cannot fight at your peak if you flinch from battle.
The same is true today. In self protection, it is vital that when you attack you attack with fortitude of spirit. If you try to attack with fear in your heart you will withdraw the attack too early for fear of the reprisal. If you find yourself needing to defend yourself, you must accept that you will almost undoubtedly get hurt. But if you attack with fortitude you hope to minimize this by defeating your foe as quickly as possible.
From a metallurgy and mechanical standpoint - another benefit of using the layering technique is that it prevents or greatly inhibits cracks from propagating through the metal. Thus, the metal in the multi-folded sword can undergo a higher level of tempering, and thus be safely harder and more brittle, because the cracks that form in the more brittle metal cannot propagate through the sword as well. Thus, you can have that hard sword that exhibits toughness (toughness, in Engineering speak, typically means resistance to failure by crack propagation).
However, modern Cr-V-Mo alloy steels make blades that, for equal method of manufacture, are so far superior to ancient blades it’s not even funny to try and compare.