Understanding Japanese Natural Stones

Josh explains the grading process and what to look for when choosing a Japanese natural whetstone.
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bernalcutlery....

[@bernalcutlery-sf]

to clarify 'toxic lines' are hard mineral inclusions that scratch the knife, they are not toxic from a health perspective.

[@Skeptic2006]

I bought a cheap synthetic 2-in-1 stone, but it developed a valley almost immediately. I'm planning to get a Japanese natural stone, but I’m worried about the same issue. Do you ever need to level them, and if so, how do you do it?

[@SenriganA]

最終仕上げは、35°〜45°に刃を立てて、小刃付けすると非常に鋭利な刃になります。

[@joshuahughes1408]

Do you think these would be good for japanese woodworking chisels?

[@toroblanco1637]

I use a very similar method to qualify a stone. I like to use a shirogami #1 knife and a Aogami super knife.

[@morehn]

How do you check that your knife is sufficiently sharp? In my class for learning kosher slaughter, we learn to run the blade against the tip of our nails to check for smoothness or any nicks, and then we check it against our skin to see if it grabs it to check for sharpness.

[@bernalcutlery-sf]

there’s different tests for sure, some use paper, shaving arm hair, fingernails, etc. I think how it performs in its intended use is the best test though

[@morehn]

I used my BBW today for the first time along with a nakayama awasedo shohonyama and absolutely fell in love with both. Now I want to explore the Belgian White and more jnats. Can you comment on some of the differences between the two or what jnat I might want to look into next?

[@bernalcutlery-sf]

Nakayama would definitely be finer than BBW, you would find more bite on the BBW edge and more razor like keenness on Nakayama. I think an Aoto would be good or a softer honyama in the 3 hardness and fineness range (1-5 scale)

[@morehn]

@@bernalcutlery-sf awesome, thank you. I felt like the BBW was similar to a hard rubber, while the Nakayama was similar to velvet. Does that sound right to you? They gripped the blade in different ways, much more noticably than the Ark.

[@bernalcutlery-sf]

sounds about right!

[@morehn]

@@bernalcutlery-sf would you recommend for my Victorinox that I need a perfectly clean edge for, with no perceptible bumps, I don't know if that's what toothy means: Tanaka Toishi Aoto Natural Stone Type 15 (Harder) Approx 1400 grams I saw that you're celebrating the holiday today, so I wanted to take advantage and put a few things in my cart.

[@seanstapelfeld]

I love jnats and coticules this video came in the perfect moment in time. I love honing on a rock that isn't man made

[@morehn]

Can you recommend a couple of stones from a range of soft all the way to a finishing stone of a 12K equivalent for a high carbon steel blade like a Victorinox Fibrox with a 56 Rockwell?

[@bernalcutlery-sf]

i would recommend a coarser polish for a softer steel like Victorinox, something in the 2-3K range like an Aoto stone is best for edge life of softer steel

[@morehn]

@@bernalcutlery-sf I just picked up an Aoto from you in celebration of International New Knife Day

[@AC-wl7ve]

Is there a real benefit of natural stones over synthetic?

[@bernalcutlery-sf]

it’s pretty subjective, but if the stone is a good fit for the knife you are sharpening it can really improve the edge retention and sharpness of the knife. That being said natural stones are not as predictable as synthetic stones so they may work well with some knives and not as well on others. Overall you may find they aren’t great for European knives and general Japanese stainless but for certain carbon steels and single bevel knives they can really make a difference.