I ran across a rather unusual weapon recently. A Katana, to be specific. Now normally I don’t give a second thought to katanas because they have been done to death. There are so many of them, all with the same basic features, and simple cosmetic differences, that my eyes I kinda just glaze over when I see most of them. Not this one though. It kinda just just popped out at me. Or specifically a couple of words that I don’t believe I have ever seen preceding the word Katana: “Double-Edged”
Now this is interesting. Traditional katanas only have a single edge, generally because it allows the sword maker to incorporate all of the strength holding and resiliency of the blade in the body and spine of the blade, while focusing all of the hardness and cutting power on the edge. Each half of the blade serves a specific purpose, together making a katana a very strong and efficient weapon.
A double edged katana is possible, but poses problems. The blade of a traditional katana usually has a differential temper from the edge to the spine. The blade is tempered differently across the width of the blade in order to get more hardness at the edge, while retaining flexibility and resiliency from the rest of the blade. A double edged weapon would make this very difficult, as you would have to sacrifice flexibility and durability in order to have the same hardness across both edges. Incidentally you would also lose the characteristic curve of the katana if you tried to temper both edges traditionally, as that curve is a natural byproduct of the differential temper process.
This means that this particular sword design is not going to be as durable as a traditional one. But the design does try to get around this problem by only making the top half of the sword double edged. And in a katana, that top half is probably most likely to benefit from a double edge. Except that now you’ve diminished the structural integrity of the blade from that point on, and under duress, against a traditional blade, this one will most likely break in half. So though the folks at Cold Steel claim it’s strong, I personally wouldn’t be tempted test the veracity of that statement.
OK, so I’ll admit the structural validity of this design is questionable. However I don’t think I’ve seen it done before on a Katana, but it caught my eye. Which is a hard thing to do, especially if you look like the average, run-of-the mill Katana. So it gets an honorable mention. Even if it is a pointless and unnecessary design feature from a purists perspective…
Cold Steel Double Edged Katana – [True Swords]