It is because we love things that we must be brutally honest about them. What is a Japanese sword? A steel bar with a blade and a point. That’s it. Now before I have a thousand people screaming at me about how the sword is the “soul of the samurai” let’s take a look at the common usage and effect of the samurai sword.To do this, I’m going to have a look at the archaeological records of the defence of Midare-bashi bridge in July 1333.
Let’s get one thing out of the way first though. The sword was not a primary battlefield weapon. For the most part Samurai and ashigaru were armed with naginata, although yari later became more popular, or yumi. The origin of the Samurai actually lies in their practice of yabasume, or mounted archery, not in their swordsmanship. On the battlefield, the sword saw the best usage as a cavalray weapon, slashing down from on horseback. Many of these swords were mounted in the tachi style, typically more curved and slightly longer than the katana we are all familiar with today, with a pronounced curve in the tsuka. Tachi are essentially cavalry sabres, and are thus suited to the Samurai’s original role.
As the catchment of the samurai class expanded, however, more and more samurai acted as soldiers on foot. During the transitional period Samurai armour went through many changes. Parts of the O-yoroi that had been fine on horseback were not practical on foot, particularly the large, heavy helmet pieces. It is for this reason that many Samurai at Midare were not wearing helmets at all, allowing them to move their heads freely. This accounts for the vast majority of wounds from swords that are found at Midare, where “7% of skulls produced ‘paired’ cuts, both done by the same weapon, where an initial cut across the victim’s left temple caused him to fall forwards, carried by the momentum of his attack, a second blow then being struck across the parietal bone on the rear of his head, generally bisecting the sagittal suture. Most of the cuts are placed with extreme accuracy; nearly all neatly bisect suture lines, or are positioned across the temple, just under the hairline. It seems doubtful that such standardisation could have been achieved if the victims had been wearing a helmet. The angle and location of the majority of the injuries suggest that they were probably inflicted from horseback, a mounted warrior taking a flat but forceful swing at his opponent and cutting him across the forehead, the tremendous momentum of such an attack resulting in the ‘skidding’ of the blade across the skull.”
The vast majority of the deaths at midare were likely caused my arrow wounds, spears and naginata (which have a cut pattern that is distinct from tachi!).The fact is that 7% is not a lot of skulls, and that seven percent is itself from a nine percent of total skulls collected that exhibited evidence of sword wounds at all (overall numbering just about 23 skulls with sword related injuries!). Just how few people died in this battle from sword cuts just goes to prove my point, the sword was not a battlefield weapon. When Samurai armour had caught up to the new infantry role of many samurai, it became clear that the sword was almost useless against armour. (If you still don’t believe me then I encourage you to go and find the youtube video from Iron Mountain armoury destruction testing a full suit of samurai armour!)
If the Sword was not a battlefield weapon then what was the point of it? This is indeed a fair question, and the answer lies in the evolution of the tachi into the katana. Where the tachi was the cavalryman’s weapon, the katana is firmly optimised for use on foot. This usage, however, was not in the heat of full on battle, but rather in unarmoured skirmishes. The katana was the samurai’s self-defence weapon, always at his side in case of attack. For evidence of this, one only needs to examine the sword schools. The vast majority of kenjutsu and iaijutsu schools utilise techniques that slash at the head, or the neck or the stomach, all areas that would be well protected in samurai armour.
So with the understanding of the katana as the Samurai’s primary self-defense tool now in place, the near religious veneration with which samurai swords are often viewed becomes more understandable. These objects were often the last line between a man and certain death, hence it was carried at all times and treated with a great deal of respect.
This is not to downplay the religious significance of swords in Shinto. The cloud cutter is indeed part of the imperial regalia of Japan and swords play a large role in spirituality and mythos. For the Samurai, however, while they would’ve recognised the spiritual significance of the sword as they would any other object that had a kami, it was ultimately a tool. Swords bent and broke all the time, and were not the almost indestructible super-weapons that we commonly perceive them as today.
It cannot be denied that the samurai sword might have been useless in all but the most dire situations on the battlefield. Against an unarmoured opponent, however, the weapon was quick and lethal, and hence the method of choice for the Samurai to protect themselves in day to day affairs.
 Arms and the Men; 14th Century Japanese Swordsmanship Illustrated by Skeletons from Zaimokuza, near Kamakura, Japan, Myra Shackley, World Archaeology, Vol. 18, No. 2, Weaponry and Warfare (Oct., 1986), pp. 247-254
Jack Horatio Buckley Sharp 2016