Hang on here. I think the main point we have settled is that a spring-steel through hardened sword is superior (yes, that's a blanket term) to a DH blade. A vast generalization, yes, but true. Am I correct in this statement? So the questions remaining are: when did Europeans develop spring steel (and what
is spring steel in the first place - is it the actual steel itself, or is it the heat treatment, or both?) and how did a actual antique European sword compare to an actual antique Japanese sword? Because as of today, a katana and a Euro sword made with the same material and heat treatment have almost the exact resistance to bending, chipping, and so on.
For the historical comparison, I have a few quotes that may help... unfortunately, most of these European sources are from before 100 AD, while my Japanese source is from 1645. But hey, it's a start.
So first we have a quote by Polybios, a Greek writer who lived in Rome for a time, and lived from 200 – 118 BC: "The order of battle used by the Roman army is very difficult to break through, since it allows every man to fight both individually and collectively; the effect is to offer a formation that can present a front in any direction, since the maniples that are nearest to the point where danger threatens wheels in order to meet it. The arms they carry both give protection and also instil great confidence into the men, because of the size of the shields and
the strength of the swords, which can withstand repeated blows. All these factors make the Romans formidable antagonists in battle and very hard to overcome."
So here we have a Roman Republic era sword being described a "strong" because it can withstand "repeated blows" - implying, perhaps, that this was out of the ordinary; in other words, an ordinary sword couldn't take repeated blows. At least, that's my thought on the quote (of course, the whole thing is moot if Polybios was talking about the
shields instead of the swords, but it doesn't seem likely given the structure of the wording). This would make since, because the sword was very much a backup weapon in the Mediterranean world. However, the sword was more of a primary weapon for the more norther Europeans of the time: the Celts.
Here's a quote from Wikipedia (https://en.wikipedia.org/wiki/Iron_Age_sword) that talks about the numerous quote by ancient authors about Celtic swords bending:
"Polybius (2.33) reports that the Gauls at the Battle of Telamon (224 BC) had inferior iron swords which bent at the first stroke and had to be straightened with the foot against the ground. Plutarch, in his life of Marcus Furius Camillus, likewise reports on the inferiority of Gaulish iron, making the same claim that their swords bent easily. These reports have puzzled some historians, since by that time the Celts had a centuries long tradition of iron workmanship.[2] In 1906 a scholar suggested that the Greek observers misunderstood ritual acts of sword-bending, which may have served to "decommission" the weapon.[3] Such bent swords have been found among deposits of objects presumably dedicated for sacred purposes. The speculation has been repeated since.[2] Radomir Pleiner, however, argues that "the metallographic evidence shows that Polybius was right up to a point. To judge from the swords examined in this survey, only one third could be described as conforming to the quality which he ascribed generally to Celtic swords. Even so, it is quite possible that even some of the better quality swords would have failed in battle."[3] Nevertheless, he argues that the classical sources are exaggerated. Plutarch's claim that Celtic swords would bend completely back is implausible, as only a slight bending would be likely.[3] Pleiner also notes that metallurgical analysis performed on Celtic swords suggests that they were only work hardened and only very few were quench hardened, even though they frequently contain enough carbon to be hardened (in particular the swords made from Noric steel). Quench hardening takes the full advantage of the potential hardness of the steel, but leaves it brittle, prone to breaking. Quite probably this is because tempering wasn't known. Tempering is heating the steel at a lower temperature after quenching to remove the brittleness, while keeping most of the hardness.
There is other evidence of long-bladed swords bending during battle from later periods. The Icelandic Eyrbyggja saga,[4] describes a warrior straightening his twisted sword underfoot in a manner similar to Polybius's account: "whenever he struck a shield, his ornamented sword would bend, and he had to put his foot on it to straighten it out".[5][6] Peirce and Oakeshott in Swords of the Viking Age note that the potential for bending may have been built in to avoid shattering, writing that "a bending failure offers a better chance of survival for the sword's wielder than the breaking of the blade...there was a need to build a fail-safe into the construction of a sword to favor bending over breaking".[7]"
Here's a thread from another forum discussing the same thing:
myarmoury.com/talk/viewtopic.php?p=166864 Contrasting all that is a quote by some ancient author who I can't remember (it's in one of my books, just not sure which one - I'll see if I can dig it up) about a flex test the Celts used to test their swords: they would hold the sword by the hilt and by the end of the blade, then pull down, thus bending the sword over the top of their heads. Then they would let go: the sword was supposed to spring into the air, and
not suffer from any bends.
Now, this is all just quotes by authors who may or may not have know what they were talking about. But here's a quote by a Japanese man who had extensive knowledge and experience with swords; someone we're probably all familiar with: Miyamoto Mushashi.
The Book of the Five Rings (or the Scroll of the Five Spheres, or
Go No Rin Sho, whichever you prefer) has many techniques that deal with striking your opponent's sword during combat. However, in the beginning of The Scroll of Wind, Mushashi is talking about the different schools of swordsmanship and the problems he sees in them. He talks about a school that focuses on brute force, and one of the problems he says of this school is: "If you hit the other's sword with a great deal of force, your sword might break in two." There is apparently some discussion about whether if should be translated "your sword might break in two" or "your sword will have a tendency to lag behind."
At any rate, there are plenty of techniques in the rest of the Book of Five Rings that deal with sword on sword contact. None of them speak about the sword breaking or bending. I do remember a technique that talks about "if you are in an enclosed area or your sword
is not cutting well anymore (it's getting dull from edge on edge contact I assume), stab your opponent" and also a technique for breaking your opponent's sword with your foot, but I couldn't find either and I may be confusing techniques in my mind.
Long and short of it all seems to be that there was no significant difference in toughness between ancient European swords and 17th century Japanese swords according to the writings - actually, it seems like the Japanese swords may have been tougher than ancient Euro swords. However, I have no Medieval European sources in there, and obviously the European quotes do not provide rock solid evidence, and all the quotes are just a small look at the whole picture.
But do we have any examples of how European Medieval swords stood up to combat?