Thank you to everyone who took the time to respond.
It sounds like Simichrome and Flitz are exactly what I am after, thank you.
I also feel I should clarify, the patina I am primarily interested in reducing is the grey and blue oxides which form with normal use. I know some like them, even prize them, but they are not my preference. I should have mentioned this sooner, I am sorry, but it honestly didn't occur to me.
In terms of the scratches which can develop on a mirror finish, thank you for thinking of me in regards to them. Previously I had not considered them a form of patina, which thinking about it now, they clearly are. To be totally honest, and perhaps somewhat surprisingly, they do not bother me. They have a certain charm to me, perhaps like the oxide patinas hold for others.
Mirror polished reactive carbon seems like a giant pain in the ass. I say this as someone who owns a mirror polished knife (that's stainless) and wouldn't buy one again.
You either need to make peace with patina or make peace with having scratches. Or spend the rest of your life polishing. There are plenty of cooks who remove the patina from their knife after each service, but zero of them are using mirror polished blades.
Thank you for thinking of me in regards to the scratches. I am at peace with the light haze of scratches which form.
A mirror finish or kasumi can probably be maintained on a honyaki sashimi knife that is exclusively used for portioning boneless skinless fish indefinitely, but for pretty much anything else getting scratches on the finish will just be part of it...
The knife I am thinking about is a V-ground nakiri, similar in appearance to a usuba with a defined shinogi line. It would only be the upper portion which mirror polished.
Simichrome is my choice, sometimes it feels almost magical. Mirror finish though…… you will see scratches anyway and there is no reasonable way to keep it mirror on a knife that is being used as even whipping with a towel can produce fine scratches. I don’t think Japanese chefs that remove patina on their working knives after every shift worry about mirror polish just to remove patina instead. Mirror finish is a whole other level of driving one totally insane.
Thank you, I was wondering what the common practice are for daily maintaence among Japanese chefs.
In terms of a mirror polish, I think one has to learn to be okay with some level of light scratching.
I am also a wood worker and I have mirror polished all my plane irons. For whatever reason, the light scratches do not bother me. Every once and awhile I may spend a minute or so touching up the finish. Not to restore a near perfect visual mirror again, but rather to just take the edge off the hard lines. Soften the haze if you will. I am happy with this.
Mirror polish will be really really sticky. It'll worsen your food release. I wouldn't bother. If I was bothered by patina (which I'm not) I might consider forcing a patina with coffee or something so it's at least an even dark color.
But if patina truly bothered me I'd just buy stainless knives instead.
Yes, that is a downside of mirror polishes.
In this case I was referring to a V-ground nakiri with a defined shinogi line, similar to a usuba in appearance. It is only the upper section in which I was considering polish. I am hoping the v-grind will aid in the food release sufficiently. I can always lightly brush it later, or give it a kasumi finish, however I hope I will not desire too.
It could really be used for either or I think. The mud itself works quite fast (5k light blue stone) and there’s nothing stopping you from grinding up a chunk of it and keeping it in a vial for daily use.
It’s not a cheap, quick or super easy option, but quite viable.
I hadn't considered using the mud before. Essentially making a polishing paste. Similar to a honing compound. Which then makes me think a honing compound might work well on a cloth. Essentially making a polishing cloth, like which is used for jewellery. It is all so obvious now.
This could be very helpful and much easier than using a stone. As someone could then polish the scratches and soften the bottoms of the scratch too. Thanks for the idea.
Even highly polished low carbon steel develops rust very, very easily. It's roughly 70% humidity in my part of Ontario right now, and just last week after brightly finishing a low carbon clad blade I set down for the night, and in the morning I found multiple rusty finger prints on the blade. I would wait for a stainless clad blade if you're absolutely set on a mirror finish.
That sounds really frustrating.
I'm in BC (in the Rocky mountains) and humidity is more stable here. That said we still actively maintain our house in the 50% humidity range. I have been blessed to not have a problem yet.
anyone one else try the koyo blue for routine cleaning?
No, nor had I previously considered it. I think it has good potential and is worth trying.
The danger I can see is, if one touches up mirror finish on a polishing stone again, the degree of polish may be different in some areas. As a polishing compound on a cloth may create low spots in the blade, which may not then match the polish achieved on a flat stone later. If so, I would probably do a light polish again with the cloth to match the level of finish, Or this might not be a problem at all.
Perhaps someone has experience here, and can share some feedback. Otherwise I am temped to polish a cheaper knife and see how this approach works over time.
. I had tried relegating certain cloths to certain stones, but I can’t seem to keep the system organized. Using a grit impregnated cloth may actually be ideal for this application. 
