The sheath comes in two types: the koshira’e sheath with lacquer and metal fittings like the tsuba (guard) and the shirasaya sheath made to protect the sword blade. The koshira’e is for outdoor use, while the shirasaya is for keeping the sword at home. The making of sheaths to protect swords requires the ultimate craftsmanship. To make the sheath, dried magnolia wood left to set for ten years is used. Magnolia wood is chosen for its lack of oil and ability to shut out magnetism. More importantly, it is also easy to fashion and prevents the sword from rusting.