# Where is the cutting edge



## CowryX (Sep 8, 2022)

I have only had a Tojiro DP & Misono UX10 gyutos. I have been learning how to sharpen on whetstones for the past few months. I finally treated myself to a nicer knife. I bought a Kobayashi SG2 gyuto. The lightness, sharpness, and lack of wedging are astounding!

If I were to take a sharpie and try to mark along the hasaki, there is nothing to mark. Where is the cutting edge? At what angle do you reckon this knife was sharpened at?


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## myguidingmoonlight (Sep 8, 2022)

The cutting edge is there; it's just a very small primary bevel, a good indication of a knife that's thin BTE.


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## CowryX (Sep 8, 2022)

myguidingmoonlight said:


> The cutting edge is there; it's just a very small primary bevel, a good indication of a knife that's thin BTE.



Thank you for the clarification. How are they able to create a very small primary bevel? I sharpen my knives at around 15°. All my bevels seem to be huge compared to this knife. Can one learn how to make small bevels like that?


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## myguidingmoonlight (Sep 8, 2022)

CowryX said:


> Thank you for the clarification. How are they able to create a very small primary bevel? I sharpen my knives at around 15°. All my bevels seem to be huge compared to this knife. Can one learn how to make small bevels like that?


From my experience, the primary bevel would just naturally be that small if the knife is thin behind the edge, even if you sharpen it at a shallow 10-15 degree angle.

A thick knife with a 15° primary bevel and a thin knife with the same 15° primary bevel would look quite different, the primary bevel would look larger in the former case.


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## CowryX (Sep 8, 2022)

Thanks, again! 

I'm dazzled by this Kobayashi. I reckon it's time to buy more thin knives


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## myguidingmoonlight (Sep 8, 2022)

CowryX said:


> Thanks, again!
> 
> I'm dazzled by this Kobayashi. I reckon it's time to buy more thin knives


No problem! 

Just to clarify, a thin knife, in this case, doesn't necessarily only slender-spined knives like the Kobayashi; knives with the thicker spines can be just as thin behind the edge too.

For example, my Heiji also has a very small primary bevel.


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## HumbleHomeCook (Sep 8, 2022)

It is indeed because the blade grind comes down very thin, or as said, thin behind the edge (BTE). Since it is so thin, the edge bevel is barely visible. Geometry reigns supreme.

This is @Deadboxhero's YouTube site:


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## CowryX (Sep 8, 2022)

@HumbleHomeCook Thank you! So much to learn, I love it! Looking forward to watching these videos.

@myguidingmoonlight That's a beautiful knife.


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## myguidingmoonlight (Sep 8, 2022)

CowryX said:


> @HumbleHomeCook Thank you! So much to learn, I love it! Looking forward to watching these videos.
> 
> @myguidingmoonlight That's a beautiful knife. What brand is it?


Thank you, it's a Gesshin Heiji.


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## Benuser (Sep 9, 2022)

CowryX said:


> I have only had a Tojiro DP & Misono UX10 gyutos. I have been learning how to sharpen on whetstones for the past few months. I finally treated myself to a nicer knife. I bought a Kobayashi SG2 gyuto. The lightness, sharpness, and lack of wedging are astounding!
> 
> If I were to take a sharpie and try to mark along the hasaki, there is nothing to mark. Where is the cutting edge? At what angle do you reckon this knife was sharpened at?


My guess is your Tojiro & Misono can use a good thinning. Send them out. 


When only the very edge has been maintained, the bevels rapidly get wider and the blade thicker behind the edge.
It's good practice to start every sharpening with thinning behind the edge. If it has been neglected for a while, it often is beyond the average home sharpener to restore the original, thin geometry.


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## sumis (Sep 9, 2022)

the kei kobayashi is indee d thin begynd the edge. also, it’s blade geometry is such that you sometimes don’t notice that the edge is dull, since it falls effortlessly through denser produce. 

.


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## Benuser (Sep 9, 2022)

Benuser said:


> My guess is your Tojiro & Misono can use a good thinning. Send them out. View attachment 197832
> When only the very edge has been maintained, the bevels rapidly get wider and the blade thicker behind the edge.
> It's good practice to start every sharpening with thinning behind the edge. If it has been neglected for a while, it often is beyond the average home sharpener to restore the original, thin geometry.


On this 30-years old Misono Carbon 240, which has lost some 10mm of width, the bevel has been painted in red. The blade isn't all that thin, but the polished backbevel is in line with the convex face.


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## r0bz (Oct 12, 2022)

Benuser said:


> My guess is your Tojiro & Misono can use a good thinning. Send them out. View attachment 197832
> When only the very edge has been maintained, the bevels rapidly get wider and the blade thicker behind the edge.
> It's good practice to start every sharpening with thinning behind the edge. If it has been neglected for a while, it often is beyond the average home sharpener to restore the original, thin geometry.


before I got into the forum i wasn't aware of geometry 
now every time i need to sharpen the edge I start with thinning


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## CowryX (Oct 12, 2022)

I have been going through many posts, learning, and practicing sharpening almost daily. I didn't want to practice on my SG2 knife. I bought a Shirogami #1, and Blue #2 gyutos. I have dramatically thinned them. I have also been getting better at keeping angles around 10-12°. 

I'm over the moon with my super sharp vanishing edges  Now I need more knives to practice on.


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