Like most swords, traditional Japanese swords were typically stored in a sheath. When the samurai warrior wasn't using his sword, he would keep it a sheath. This served several purposes, one of which was to protect the sword from damage. Without a sheath, swords were exposed to the elements and more likely to sustain damage.
Additionally, a sheath protected the samurai warrior from self-injury. When a sword was properly maintained, it would feature a razor-sharp edge that could easily cut into the skin. So, samurai warriors would carry their sword in a sheath to reduce the risk of self-injury.
Traditional Japanese swords were typically stored in one of two different types of sheaths: the shurasaya or the jindachi-zukuri.
To learn more about these sheaths and how they differ, keep reading.
#1) Shirasaya
Perhaps the most common type of sheath in which traditional Japanese swords were stored is the shirasaya. It was made of hand-carved wood with a curved shape to accommodate the katana's curved blade. A typical shirasaya featured two pieces that jointed together, one of which was longer than the other. The small piece could be removed by pulling up; thus, exposing the sword's hilt and allowing the samurai warrior to quickly draw the sword.
The shirasaya is a relatively simple, easy-to-produce sheath, making it an attractive choice for mass-production. And because it was made of wood, the shirasaya was often used for long-term storage. This is in stark contrast to the jindachi-zukuri, which we're about to explain.
#2) Jindachi-zukuri
A second type of sheath for traditional Japanese swords is the jindachi-zukuri. While the shirasaya was used primarily for long-term sword storage, the jindachi-zukuri was a more battle-ready sword sheath. It typically featured embellishments and decorations, and was worn either on the belt or by straps. When worn by straps, it was referred to as a tachi-style jindachi-zukuri.
The jindachi-zukuri was more difficult and time consuming to produce than its shirasaya counterpart. The individual making the jindachi-zukuri would often carve intricate details into the side.
Of course, there were other sheaths designed throughout feudal Japan. The shirasaya and jindachi-zukuri were simply the two most popular. The shirasaya was a more basic sheath used primarily for long-term storage, whereas the jindachi-zukuri was a battle-ready sheath with intricate decorations. Hopefully, this gives you a better understanding of the two primary sheaths used for traditional Japanese swords.