Interesting leathery look. Without the historical significance I wouldn't pay a lot for it but enough there to appreciate it for what it is.
Aesthetic appeal is very individual and personal. Everyone has their own preferences and value changes accordingly.
Came across this, curious if this is an example of a blade that has been re-tempered? Looks a little funny in some spots/angles.
https://www.facebook.com/pg/Samurai-sword-and-others-311039152711539/photos/?tab=album&album_id=842749512873831&ref=page_internal
Anyone disagree that the suriage waki blade below is likely a Izumi no Kami Rei Kinmichi?
Little uncertain about the center of the crysanthemum is circular vs star shaped.
Additional pictures: https://www.facebook.com/pg/Samurai-sword-and-others-311039152711539/photos/?tab=album&album_id=798632290618887&ref=page_internal
https://nihontoclub.com/smiths/KIN44
http://www.nihontocraft.com/Mishina.html?fbclid=IwAR2Li8f4g_n3f9K5oejfRQoK-O9bV2Q7LV0UCAT40XFPD0kgMV7gyl_6Whk
Control example..
Hi Florian,
Im thinking it might be oil residue. I use 91% Isopropyl to remove all old oil prior to adding fresh oil as part of my maintenance routine. You might try that.
As long as you keep the blade lightly oiled and inside the airtight saya/shirasaya, all should be ok (assuming proper humidity levels below 60%). I believe Koshirae can be a bit more temperamental and also doesn't like humidity levels that are too low. Lacquer, leather etc can require extra care.
Sorry that's just from memory, don't recall where it was from. I was researching it last year to determine if open blade display was feasible or not. Ended up deciding against it.
Is this testing renessance wax? From what I remember reading the wax will protect for years but the properties change over time and it will haze gradually as it ages. It's also difficult to remove due to how the properties change over time, perhaps it dries and hardens or something. So I don't think testing removal after a couple days will be an accurate test.
For example sake, let's say a blade is valued at $2k. I think you will find that if you spend $800 shipping a blade to Japan for NBTHK shinsa and obtaining hozan, it wouldn't typically increase the value dollar for dollar unless a favorable finding is uncovered in the process. Same goes for polishing. So you will typically save money buying a papered / polished blade.
Yes flaws will detract from value, however a generally tired blade is more accepted from Muromachi or prior. I don't see anything too alarming here. Looking quite nice ????
Just speaking from my personal experience and what the practitioner world generally agrees on. Not a Hanwei dealer but I would say I am biased with them due to each piece, at thier respective budget, seems to be a great bang for the buck for the modern day practitioner. Il let you continue with your research, stay safe.