Face it, you're not getting your hands on an antique pre-Edo sword for less than a lot of money. Also, you don't want one. Unless you are into museum display pieces, then go ahead and spend to your budget's content.
If you are looking to purchase an authentic Japanese katana you are most likely looking for something functional. It's fair to say that when looking for authentic swords you want something in the style of with the qualities of.
Fighting with antiques comes with a laundry list of reasons not to do so. For those that want to train and fight with modern martial clubs, you need a solid weapon that works like an authentic antique but doesn't shatter or cost a fortune.
This guide is for those looking to use the weapons of the past as they are made today.
Authentic Japanese Katana Qualities
One of the other reasons you don't want an antique Japanese katana is that they really don't hold up to modern blades.
As any aficionado knows, the mystique around the katana is one part truth and two parts fluff of the telephone game. The iron in the areas of Japan is of notoriously low quality, which made crafting weapons difficult.
This lead to superior iron smelting and sword crafting techniques. Necessity was, as it often is, the mother of invention.
Modern materials make far better swords but modern materials and ancient techniques make authentic, functional works of beauty. That's what you want, and that's what you'll find here.
Finding a steady supply of genuine Tamahagane steel is both impractical and difficult. This was the steel so filled with impurities and problems that it required developing of lamination and folding techniques to create something workable.
For the most authenticity, folded steel of the carbon or spring varieties is possible to craft a grain pattern but folding steel comes with its own set of complications. Any problems in the folding process create gaps, and therefore brittle areas, in the sword.
Your best choice to get a real Japanese katana is to get one made of modern steel (one that the samurai of old would very much kill to have) and see that it's shaped in the traditional ways.
Carbon steel offers the cheapest set of strengths to forge a sword with. Using carbon steel (not stainless steel), a smith creates a long-lasting blade that holds an edge and remains strong.
When looking for carbon steel katana, you need something that is 1045 or better. That is carbon steel with 0.45% carbon or better. The more carbon, the keener an edge that can be formed.
Spring steel takes the advantages of carbon steel and adds a touch of silicon to create a metal that returns to its original shape more easily.
Spring steel katana can take a beating and still perform well and look good. The most impressive of spring stell, the 9260 can be bent to almost 90-degrees and return to its original shape.
For beginners learning to make a cut, this can be a valuable starting blade.
Tool steel uses tungsten in its alloy. These steels are, as the name suggests, often used in making tools. hammers can be used all day without deforming or chipping.
Tool steel katana make excellent training weapons as they won't nick or warp.
The blade shape of a katana owes alto to the forging technique of clay tempering.
Clay tempering creates the pattern on the blade known as Hamon. The variation in hardness created by the clay tempering both creates the beautiful wave patterns along authentic katana but also gives the signature shape.
Because the blade is more rigid than the spine, the sword deforms into a curve to balance the tension. This shape, of course, also provides subtle benefits when cutting as it moves the center of gravity and the cutting surface further along the blade.
A resulting cutting stroke gains more power after the initial contact. This 'bite' of the blade and follow-through from the fulcrum of the blade and the arm of the wielder deliver a lot of power without creating reverb.
The tang of a real katana goes to the end of the handle. The handle is attached with pins and then wrapped. Cheap knockoffs weld the handle and handguard to the blade and a few inches of tang.
These easily separate with repeated uses, shredding the hangle and leaving your blade unusable. You may not want to take apart the hilt and grip of your sword but it's a solid trait to look for in authentic weapons.
Traditional Tamahagane iron requires folding and hammering to forge. While the folding isn't necessary with better steel alloys, the hammering is still a necessity of the process.
A cast or molded blade lacks many of the strengths of an authentic katana. If you've ever seen a cheap imitation blade sold in a catalog or on television, it has probably been cast. These 'blades' don't hold an edge, are easy to bend, and can shatter from impurities in the casting and tempering phases.
The process of monotempering is sometimes used to create katana that are generall okay but not authentic. A good practice or training blade that carries the same weight and shape, but lacks many of the more important characteristics.
Hand hammering, though nice, is not a necessity. Industrial hammers make more even strikes and produce blades faster.
Find Your Blade
Now that you have a functional understanding of what makes an authentic Japanese katana, you can look for these hallmarks when shopping. Any vaguely sharp bar of iron can be used as a sword, but there's a charm to the real deal.
When shopping for a katana, choose a supplier with a passion for swordcraft and authenticity.