I have 3 Nagura, a Botan, a Meijo, and a Tenjou. I read somewhere that the Tenjou and Meijo were basically the same.
Do I need another for my Jnat of unknown origin?
Do I need another for my Jnat of unknown origin?
I think you want finishing nagura from pieces of other base stones these are frequently referred to as tomo nagura (though IIRC a true tomo is apparently a slurry stone from the same base stone?). This is where Jnats are fun IMHO and yes, a wonderful waste of time. I don't use a full botan-mejiro-tenjou-koma-tomo progression much. I like to use different base stones of varying degrees of grit/hardness. I do like a Koma but those are pricey. My koma is fairly small but works well.
You can see there is an endless of variety of fun to be had by combining this with that. But YES get a good finishing nagura from a reputable vendor that knows razor honing. JNAT duds are a dime a dozen and I am sure most have had their share of duds. There is a popular member here that sells JNATs and nagura on ETSY that are truly razor grade and wonderful products. I don't want to break any rules or step on toes so a bit of detective work will sort that out.
I think conventional thinking is something like botan/tenjou/mejiro/koma/tomo.
Are you doing one-stone or coming from synthetic at some point?