Blue lacquer sayas are durable when treated correctly, but they do require some basic attention. Avoid exposing the saya to prolonged direct sunlight, which can cause the lacquer color to fade or develop hairline cracks over time. High humidity is also a concern — store the sword in a climate-controlled environment, ideally between 40–60% relative humidity, to prevent the wooden core of the saya from swelling or warping, which can cause the lacquer surface to chip. When handling the saya, clean skin oils off the surface with a soft, dry cloth rather than any chemical cleaner, which can dull the finish. The blade itself should be lightly oiled with choji oil every few months to prevent oxidation, applied with a soft cloth and wiped to a thin, even coat. Store the ninjato horizontally on a sword stand rather than vertically to prevent stress on the habaki and koiguchi over time.
