Traditional Honoki wood, selected for being free of knots and other defects, and for having a good grain, is aged for ten years to produce a very stable foundation for making saya, tsuka, and tsunagi. The wood is salt free and has a very low moisture content compared to other woods, making it ideal for koshirae and shirasaya. There are also compounds inthe wood that deter insect attack.
A tsunagi holds the koshirae together when the blade is in shirasaya. The blanks are available in two sizes.