Sharpening a large caidao - unsure about bevel(s)

[Balthazar]

Two days ago, I received my first caidao (it’s also my first carbon steel knife). It’s the Shibazi S210-1. Pictures here.

IMO, It’s a lovely knife from a looks, weight and dimensions point of view. However, it’s not very sharp out of the box, and I’m really lost in terms of how I should sharpen this thing.

I’m not at all an experienced sharpener, and I’m still trying to improve my technique on the smaller knives I have (in particular maintaining a consistent angle as I sharpen). The issue with my new knife if somewhat different, though. It’s the knife’s bevel, I haven’t seen anything quite like it.

Side 1

Side 2

On side 1 (the left side when I’m holding the knife in a cutting position) there is, as far as I can see, no bevel. Or is the rather high, slanted area at the bottom considered a bevel?

On side 2 (right side when holding it), there is a bevel.

So how would one go about sharpening this thing? Should I only sharpen the side with a bevel, and do nothing to the other side?

Apologies for the extreme amateurism displayed here. I’ve tried to do a bit of searching but haven’t found much useful information. The other caidao’s I’ve used (at my mother-in-law’s) have had normal 50/50-bevels, and when I ordered it I imagined this Shibazi did too.

On a side note, any ideas why the knife edge is shaped as it is? Are there any benefits to this?

As for how to hold and move the knife during sharpening, I assume the advice dispensed in this Korin Knives video is to be trusted, (although the cleaver used there is much more pronounced curve than mine), if there are other useful instructions for (vegetable) cleaver sharpening out there please let me know

[video=youtube;lWlg5dDujwM]https://www.youtube.com/watch?v=lWlg5dDujwM[/video]

Thanks!

 

[Benuser]

Don't expect figures here. With the marker trick, you may sharpen any blade, provided you want to stay with the current configuration.
Your blade obviously has a strong asymmetry. Just follow the existent bevels and you should get it all right.
Start at the right side with a very low angle . That will abrade far behind the edge. Raise the spine little by little and verify the progress by looking at the scratch pattern. Paint the edge with a marker, and see where the ink has gone. Go on with raising the spine, until all ink has gone and you can feel a clear burr on the other side. That's the moment to flip sides and start on the other side. You should now go on until there's a burr on the right side.
Now, strop both sides to reduce the burr as much as you can. When the burr only flips without getting any smaller it's time to go to a finer stone. Repeat the whole procedure. Finally, deburr with longitudinal strokes.

 

[Benuser]

https://m.youtube.com/playlist?list=PLEBF55079F53216AB

 

[Balthazar]

Thanks for the suggestions! The blade is definitely assymetrical. The thing is that I’m not able to find a bevel at all on the left side.

Close-up images:

Left:

Right:

So since I’m not able to see any bevel on the left side, does that mean I should be angling the knife so as to sharpen the whole «lower region» of that side, as in the image under?

I'll go with your suggestions for sharpening the right side. John's videos are great, I've seen most of them, but I thought I might need to take a different approach with a cleaver due to the size of the thing.

 

[mikaelsan]

im loving mine so far, but i removed the factory edge before i even began using it, started out by putting a somewhat compound edge on it, then recently just thinned it again

 

[Benuser]

Perhaps the left side has only been deburred. There's a bevel, even if it hardly noticeable.
Just to give an idea, on a piece of leather, have it flat, move it forward in the direction of the edge while you raise the spine little by little until the edge bites into the leather. It might be at quite a high angle. Paint the edge all along.

 

[Balthazar]

im loving mine so far, but i removed the factory edge before i even began using it, started out by putting a somewhat compound edge on it, then recently just thinned it again

Cool, is yours a Shibazi too, or is it another caidao?

Perhaps the left side has only been deburred. There's a bevel, even if it hardly noticeable.

You were right, I did find a very small bevel on the left side, and after some sharpening and deburring it became quite visible:

The sharpening was a real joy too, I've never sharpened carbon steel before. I ended up sharpening it pretty much the same way I would a smaller knife (i.e. in accordance with Jon's videos), and I used the magic marker method.

The knife is now a whole lot sharper than it was.

However, I went about it real slow, used a good 20-30 minutes to sharpen it, and as a result rust seems to have developed. So I discovered both the joys and horrors of carbon steel, all in one sharpening session .

The rust is clearly visible on the image above, but here's another one to make it even clearer:

So now I have to read up on derusting. I have some Autosol polish at hand, which I hope may prove useful for this. Do let me know if you have any recommended methods/links

 

[Benuser]

Come on, that's hardly rust! Well technically it is, but nothing to worry about. Take it off with any towel, rinse with a lot of very hot water, repeat this a few times. It will darken and you will have got a patina, a further oxidation of common rust that's much stabler.

 

[mikaelsan]

Cool, is yours a Shibazi too, or is it another caidao?

So now I have to read up on derusting. I have some Autosol polish at hand, which I hope may prove useful for this. Do let me know if you have any recommended methods/links

It's the exact same model as yours 🙂 I don't think the reactivity is bad, but that's a matter of opinion I guess, don't worry too much about patina and rust, just remove it if it's red/brownish, just wipe out dry after use. But again that's my personal opinion

 

[Balthazar]

Come on, that's hardly rust! Well technically it is, but nothing to worry about. Take it off with any towel, rinse with a lot of very hot water, repeat this a few times. It will darken and you will have got a patina, a further oxidation of common rust that's much stabler.

Haha, alright then, that's good to hear. Thanks again!

It's the exact same model as yours 🙂 I don't think the reactivity is bad, but that's a matter of opinion I guess, don't worry too much about patina and rust, just remove it if it's red/brownish, just wipe out dry after use. But again that's my personal opinion

Cool, I'm quite surprised you have the same model. How long have you owned the knife? Not that it matters a whole lot, but since you have the same model I thought I'd ask: I noticed one reviewer on Aliexpress mentioning that the black area at the top had started to come off (as if it were paint/coating), have you experienced this?

 

[mikaelsan]

Haha, alright then, that's good to hear. Thanks again!



Cool, I'm quite surprised you have the same model. How long have you owned the knife? Not that it matters a whole lot, but since you have the same model I thought I'd ask: I noticed one reviewer on Aliexpress mentioning that the black area at the top had started to come off (as if it were paint/coating), have you experienced this?

Well okay technically mine is the slightly shorter version the s210-2, I was quite curious about this to, another person reviewing said it had a very durable ku so yeah, only for less then a month 🙂 I gave it an initial thorough wash when I got it, and I think it faded ever so slightly, but is definitely still there after a few weeks with light usage, and does not seem to be going anywhere
This is only my second ku knife, so for all I know it might just be blued, don't actually know, would not know the difference if I had it in hand

 

[Balthazar]

Well okay technically mine is the slightly shorter version the s210-2, I was quite curious about this to, another person reviewing said it had a very durable ku so yeah, only for less then a month 🙂 I gave it an initial thorough wash when I got it, and I think it faded ever so slightly, but is definitely still there after a few weeks with light usage, and does not seem to be going anywhere
This is only my second ku knife, so for all I know it might just be blued, don't actually know, would not know the difference if I had it in hand

I see, I was considering the 210-2 as well, but ended up going for the largest option thinking it'd be slightly preferable for scooping and cutting the huge amounts of Chinese cabbage I often have to deal with.

By the way, what does "ku" refer to? Google didn't offer much help

 

[mikaelsan]

I see, I was considering the 210-2 as well, but ended up going for the largest option thinking it'd be slightly preferable for scooping and cutting the huge amounts of Chinese cabbage I often have to deal with.

By the way, what does "ku" refer to? Google didn't offer much help

It's my first real cleaver, the size is not as intimidating as I thought it would be, Short for kuro ochi, because I can never remember how to spell it ^^

 

[Balthazar]

I see! Thanks

 

[chinacats]

KU is kurouchi finish...I believe the process is less expensive since it is formed during making of the knife and just not removed (call it rustic). As to "rust" formed during sharpening, you can use the slurry from your finishing stone to remove it.