Samurai Swords are seen as single piece, while they are a compound of different parts mounted together to form the final item. Samurai Swords or Katana are therefore the perfect composition that the Sword Smith make carefully to keep an overall design of the Katana. There is a piece that is considered the Symmetry plan of the Katana, which is the Tsuba.
Actually, every single piece, except the Habaki, has its equal or the piece that can be compared to it. The blade is compared to the Tang and Tsuka, the Handle, can be compared to the Saya considering that symmetry plan. Even the pieces forming the great parts can be paired with similar pieces ; they certainly have different names but are supposed to compare to each other.
But there are pieces that are more comparable than the others, they even keep the same name being on the Blade side or the Tang side ; they have also the same function regardless their positions. They are called Seppa, and are known by Spacers.
What are Seppa?
Seppa or Spacers are pieces that are placed in the area between Tsuba-Habaki and the area between Tsuba-Fuchi. They are twin pieces that have the same look and dimension. Seppa are ellipsoidal and thin little dishes. They inherit the functional holes of the Tsuba -which means they have the triangular hole where the blade has to fit and the two others additional holes if they happen to be present- and may carry some prints of ornaments of patterns.
The basic function of these pieces is to ensure the tightness of the mounted pieces of the Katana. Seppa Katana are placed between three complexes of pieces that are destined to interact with each others; thus Seppa ensures the best interactivity without major alterations.
The role is therefore to ensure a relative separation of the piece groups to enhance the durability by preserving each group form being negatively affected by the next one, in case of looseness or damages received during use.
At first view, Seppa Katana seem to be perfectly the same but there are some differences. Actually they are not exactly equal in size: one fits the Saya, therefore it fits the upper Seppa Dai -the area surrounding the Nakago Ana, the central hole of the Tsuba, but it lets visible the ornaments carried by the Guard, the other fits the lower Seppa Dai of the Tsuba and it faces the Tsuka and it exceds a little the Fuchi piece
They are supposed to prevent Habaki from being in direct contact with Tsuba and Tsuba from being directly linked to Tsuka. This separation is essential when it is about conducting repair or restoration processes.
Seppa are associated to Sekigane, which are often pegs of Red Copper used to fill in the void left between Seppa and the Tsuba; they crashed during the mounting process to ensure the perfect tightness and to support the Seppa.
Seppa are made of Copper or alloys of Copper such as Brass and Bronze. These metals and alloys are particular of being soft enough to be hand forged : Seppa are handmade from the first steps to the polishing and finalizing process. The softness is exploited to ensure tight contact without scratching. The pieces made of these materials are easily removed for maintenance and repair operations.
The soft nature of these material make them susceptible to receive the damages and serve as shock absorber ; for this duty they are very good candidates and they are easy to replace. Also, they are cheap materials and they are easily acquired, though the pieces they serve for are very importatnt and essential for the Sword mounting process.
The small size of Seppa has definitemy implicated the use of such materials : the suceptibility of these soft alloys to handforging processes make shapig and printing patterns easy and reduce them to simple tasks.
Some collectors and Sword Holders tends to request Spacers made of precious metal such Gold. Actually the most important prperty is to be soft metal, expensive or cheap metal is exclusively the choice of the Sword holder. In major cases, the metal choice depends on the budget of the demander; it can also be function of the Katana purposes and the overall design of the weapon.
The Spacers are made up on pattern printed on the Seppa Dai, both above and below Tsuba. The pattern are drawn on wood pieces. The Ana that figure on the Tsuba are reproduced and perform by eliminating the material to free the spaces.
Then these wood piece are used to create molds where melted material is versed and let cooling. It is frequent to add some ornaments on the border of the Spacer. The polishing works and fitting processes are made by testing the different holes against the pieces that are destined to go through; the hole that reproduces the Nakago Ana is tested against the blade and the other holes if they exist are tested againt their corresponding tools.
The Thickness of Seppa is determined by the polishing. It is recommended that the twin spacers have the same thickness, but mot importantly that they have the same holes’ size to not ti better fit the Blade and ensure their duty.
Customizing Seppa is done by simply selecting the suitable pair from a provided list of items. Te prize is function of the material of which the pieces are made of and the complexity of the ornaments
Generally, the pieces are supplied at very affordable prices the first time and may be more expensive when proceeding to replacement. Some Seppa designs are free of charges and provided with the Katana. Some others may implicate extra fees. In all cases, Seppa are worth the money because there is no perfect Katana without well done and proficiently mounted Seppa.