These are standard highlights found with Choshu tsuba. Here is mine of similar style Kawaji Han Masasada. The one you have 3rd. John
BTW, I think they are mercury gilding.
Michael. As you can never be sure of the blade's integrity it might be safer to not use it for tameshi. One small flaw could be dangerous if not fatal. Just a word of caution. John
Toushou 刀匠 as the paper indicates are so wide ranging in design, but, quality of iron/ steel is usually pretty good. Maybe that is the telling factor. John
That's no big problem. It'll be around $1500 to polish, add the Saya restoration and it goes upwards a bit. The main thing is that it is an heirloom and at some point may be worth it as a memoria. John.
Debra, you are developing some bad rusting there. It needs a polish. Until you either have it restored or sold, to prevent further deterioration use sewing machine oil on the blade. John
I prefer a tighter hada, but, if it is occasional adds character especially if the smith is known for it. If too coarse all it makes me think is that it was forged quickly with less care. So, it is subjective to criteria. John
Yes, more effective indicating what it isn't. Still an interesting experiment. Here is a screen-shot pointer to an article where colour of bronze may indicate content. John
I have been there a couple of times and it remains my favourite castle. It is a must visit and the tea houses and ceremony guests may join are educative. Not far away is Reigando as well. John