Originally, 刀 (かたな、katana) was simply a catch-all term for a blade, meaning, a metallic, bladed object such as a sword or knife.
After the unsuccessful Mongol invasion, samurai had personal experience with being attacked at high speed and at close range. The Mongols, you see, did not just use bows; they also used close combat against any target they could get away with it against. On balance, they had much more success against the samurai with their slow-to-draw 太刀 (たち、tachi) style swords than against Western knights.
Recognizing they had a problem, samurai demanded that swordsmiths produce a sword that was faster to draw. Smiths developed a curved blade which was worn with the edge facing up while still sheathed. This allowed drawing forward and, to a small degree, outward. While the concept of drawing and attacking simultaneously came much, much later, long after battlefield use, the upshot is, a drawn katana is immediately ready for action in several directions.
This sword became recognized as the katana, as distinct from the older tachi, or “long sword” (as distinct from short swords, or tanto, and sidearms, or wakizashi).
In my upcoming eBook, The Allure of Japanese Swords, I give a concise explanation of why swords work that elaborates on the physics of cutting. The katana is in a “sweet spot” combining reach, agility, resilience in the cut, swinging speed, a wide blade, and an exquisitely sharp edge.
The katana is not as long as the yari, or spear; in groups of packed men, the yari was the more practical weapon (and furthermore, the far less expensive one). However, in an individual confrontation, the katana is a work of wonder that is flexible and can be used to overcome any opponent a samurai of the day would have faced in battle.
You can even thrust with a katana (that’s why they have tips), though it’s not the ideal use of the weapon, either.
In Miyamoto Musashi’s The Book of Five Rings, Musashi writes about using real katanas (not toys for training) in real fights. At the time of writing, the long civil wars had come to an end, but duels and at any rate, simple criminal violence, still occurred. He writes about the critical importance of follow-through, the under-appreciated value of the draw cut (cutting by drawing the sword across your opponent’s body), and that you can do lethal damage with far less “force” than is generally assumed.
Put simply, a katana is not an axe. You don’t need to chop your target.
While the katana, and other Japanese swords, deserve all the love they can get, my eBook is meant to be compact and meant to reward you, the reader, for your time. It is meant to enlighten you about swords without burying you in specialized terminology.
I realized that the best way to communicate my appreciation of Japanese swords is to write in plain English.
The Allure of Japanese Swords will be released on July 30, 2010. The cover will be unveiled soon.