Nagura – assessing the quality/use of naguras

[Yaoshi]

Good day everybody,

In the last 4 years, I have been testing various naguras because I want to define my nagura’s best use/function. Basically what I was looking for is how I could fit my tomo naguras in a similar category that asano uses: from coarse to fine: Botan, tenjou, mejiro, Koma.

In the end I decided on some attributes that I look for when assessing if a particular nagura is more or less suited for finishing a straight razor.

In this particular order:

• Fineness (finer is more desirable). I determine this attribute by feeling the slurry while honing.
• Hardness (harder is more desirable). I determine this attribute by timing how long the nagura needs to generate a certain amount of slurry.
• Speed (faster is more desirable). I determine this by timing how fast the slurry darkens.

An interesting fact I observed is that hardness does not equal fineness. There is a difference between hardness and fineness and there is no linear relationship between them: The harder the stone does not necessarily mean that it gets finer. By fineness, I mean what in the synthetic world is described as “grit level” (1k, 3k, 10k…). I have very hard naguras that produce a very gritty slurry and on the other hand very soft naguras that produce a silky, very fine slurry.

Premise:

• I am talking strictly about Japanese natural naguras here.
• I don’t have an asano set but a bunch of different tomo naguras.
• I know that the only way to assess the potential of a nagura (or honzan) is honing a razor with it and then test shaving it. However, I am looking for generalizations/rules that give me a broad orientation/indication while working with and testing naguras.

From your experience what determines if a nagura is suitable for finishing a straight razor?
Which characteristic is usually an indicator for a quality finishing tomo nagura? Feeling, grit, hardness, fineness, feeling?
How do you categorize your naguras?
How do you test your naguras?

Of course, this is no science and there are many variables involved which I cannot control, but I find general rules or guidelines very helpful to have at least a broad orientation when trying to assess the quality of a nagura.

 

[Gamma]

From your experience what determines if a nagura is suitable for finishing a straight razor?

Repeated honing results, both visual - under extreme magnification as well as critical shaving evaluation.

Which characteristic is usually an indicator for a quality finishing tomo nagura? Feeling, grit, hardness, fineness, feeling?

Everything factors into the equation/evaluation.

How do you categorize your naguras?

The interactions between multiple Awasedo and various Nagura is a fairly dynamic chain of events. I leave things fluid, without absolute blacks and whites. Attempts to apply typical categorization concepts gets in the way of my approach. Some nagura are softer, I know which ones they are, same for the harder types; some have a history of being one way or another with different stones, I know their personalities and call on them accordingly. I don't always use the same stones, same nagura, or want the same exact results. So things change, constantly.

How do you test your naguras?

By honing with them over and over again, trying new things, pushing limits, etc.

It's impossible to exhaust every single possibility, but iI try to continually try and explore as many as possible.
Sometimes, seemingly gritty slurry turns out to be finest of all, when it's worked correctly. Other times not though. It all depends on how the nagura gets along with the Honzan, the user, and the blade in question.

Other times, seemingly silky slurry becomes exhausted before the edge gets 'there' and other times it turns out to be just softer, not neccessarily finer.

A lot goes on in all of this Jnat jazz; constant experimentation and comparison and staying in-tune with the stones by using them very regularly is the only path that works for me. FWIW, I have many Botan, they're all different. While the results from using them will show that they're all coarser than my Tenjyou, there are times when a particular Botan will not fly in a particular progression, and then other times that stone may excel.

 

[Yaoshi]

Thank you Gamma for sharing your insight.
I think your approach is more detailed, broader, complex, richer and much more insightful than mine is.

As long as I don't have much time and your experience I prefer to keep things simple in order to get feasible results that I can reproduce.
In the end I believe that we both enjoy honing with naguras on honzans.

All the best

 

[Steve56]

Pretty much agree with Keith, you just have to try them with different hones and razors. It’s a trial and error kind of thing.

i have several finishers and nagura that I like, which I’ve selected over time. I usually begin testing a new finishing nagura by using it with a stone of known quality/characteristics. By comparing the razor’s edge made with the new nagura to the known, I get an idea of the fineness, speed, etc. I begin by testing HHT, and then by shaving.

 

[stone and strop]

I usually begin testing a new finishing nagura by using it with a stone of known quality/characteristics. By comparing the razor’s edge made with the new nagura to the known, I get an idea of the fineness, speed, etc. I begin by testing HHT, and then by shaving.

This exactly.