Keep Katana in shirasaya for display?

[Promo]

On 12/28/2020 at 12:10 AM, Katsujinken said:

 

I suppose that depends on one's risk tolerance. I live in the northeast US, and the humidity inside my house ranges from 25% to 65% during the year. I store my juyo blade in shirasaya, inside of an anti-corrosion bag.

The tachi I had obtained earlier this year spent his life since 1945 in a shirasaya inside a wooden box - it still had some rust pittings. So I guess storing it inside a shirasaya does not protect a blade from rust, especially since you wouldn't see rust that soon if you just store it this way (you don't take all your blades out of shirasaya daily, do you?!). Therefore assuming a blade is in shirasaya then again in a permanently closed bag for conservation I think it will be tough to check if it requires some additional care. So I would assume if I displayed a bare blade I would see it more often and therefore also oil and care more often and easier, plus if nothing can touch it aside of the air, it depends on the air where you live and how you live - or do I understand this wrongly?

[Gakusee]

Georg

There are many ways rust can still develop within a shirasaya : if the blade was touched with a bare finger and the owner did not notice (that is why I handle my blades when I view them with plastic gloves) or someone breathed on the blade or a saliva/sweat drop fell on the blade, and the owner replaced the blade within the shirasaya without properly removing either of those. Remember, a shirasaya is not watertight or airtight anyway but is more airtight than an open display cabinet. So, yes, frequent care and maintenance are required regardless of how you choose to store your blade. But
the most important thing is to take particular care of the blade in the first 6 months after fresh polish until the ferro-oxide layers on top have stabilised. I have been told that a newly polished blade is most sensitive and it “sweats” in the aftermath of the polish and one needs to regularly oil and clean, oil and clean etc  - more frequently than afterwards. 

[PNSSHOGUN]

We are missing the point here, the Shirasaya is not a magical thing that will stop all damage and rust no matter how badly it is treated. In your case the sword had obviously been neglected for decades, neither oiled or maintained correctly. If it had been out of the Shirasaya since 1945 it would be a total loss.

 

The point is not to be able to see if rust is forming, it's to do everything to stop that from ever happening.

[Katsujinken]

The last two comments are spot on. I’ve got nothing to add! :-)