Part of the japanese katana--nakago (tang)
However, as a fairly typical Japanese sword, it is deeper than this-because this "hidden" part of the sword usually contains many secrets and stories, its quality can make or destroy a sword.
Inexpensive, decorative stainless steel Japanese swords usually do not have the full tangs shown above, but spot welded rattail shanks, which makes it almost impossible to fix the handle and blade assembly together.
In addition to the obvious function of connecting the handle to the blade-nakago is a designated, rather inconspicuous place on a Japanese sword, with the manufacturer's mark or mei engraved on it.
Not all functional entry-level swords have or do require Mei's signature, but it is extremely important to antiques and should never be polished or cleaned, but must be kept in its original condition.
Indeed, this is a common mistake made by novices, which is oiling or trying to polish the hilt of a Japanese sword-traditionally, you allow it to form a protective bronze with black rust. When disassembling the samurai sword for repair, please do not do it in any way Clean or remodel it.
But the hidden signature of the blacksmith who made it is not the only secret of the guard. Many times, if you go to the museum to see real antique Japanese swords, you will find that some of them are filled with holes called "mekugi-ana" (holes for mekugi nails to be inserted).
This is because, when reinstalling, the tsuba (hand guard) position and the area where the handle is wrapped are different for each installation, so the same hole is usually not used. Because this is very common in history, modern sword collectors should not be afraid to drill a new hole in the middle shield when reinstalling-in fact, in most cases, this is inevitable because there are no two installations. The location is in the same place.
The most common problem with the Japanese sword tang is that in addition to the inherent fragility of the rat tail handle on the decorative sword, there is also a poorly shaped nakago.
This poor surface treatment under the hood may put excessive pressure on the rest of the blade, and even transmit vibration directly to the handle body-so much so that the end result may be like this
The only way to prevent this from happening is:
1) Buy from reputable sources and manufacturers that solve these problems from the source.
2) Check every sword you receive to make sure that the shape of the tang is as clean as possible, and there are no obvious defects or poorly processed parts.
I hope this information on Nakago has been helpful.