How to sharpen a Moritaka AS knife

[ValeryD]

Hi here,

I am new to this forum and I am a newbie in kitchen knives (about a year). And I have a question.
Several weeks ago I bough my first true japanese knife - Moritaka Hamono's Aogami Super 170mm Santoku.
A very nice knife overall. Me and my wife love it.
The question is simple. On the moritaka site in the FAQ I read that they advice about 5 degree (per side) sharpening angle. However the knife has a tiny micro-bevels on each side and they are definitely not a 5 degree. Something 10-15 degree. The knife cuts well, but not as good as my wife's Shun Hiro SG2 Santoku 5,5".
The question is: do I need to sharp the knife at about 5 degree per side without microbevel or do I need to give it to a sharpening man who can make also a microbevel?
How do you, guys, sharpen similar knives? Do you use a microbevel or just sharp them at 5-7 degree (per side)?

Thanks in advance.

Valery.

[Altadan]

Hi Valery,
Welcome to the forum, and congratulations on your first buy

I think most of us would not overthink this.
Moritaka's AS steal is known to hold acute edges very well. Whether you're sharpening freehand or on some sort of jig, just go for a 5-7 degrees on either side. It's really up to you and your (developing) preferences to decide whether or not you want to add a microbevel to that.
Screaming sharp - no microbevel
Longer-lasting edge - yes microbevel.

I hope this helps,
Dan

[ValeryD]

Hi Valery,
Welcome to the forum, and congratulations on your first buy

I think most of us would not overthink this.
Moritaka's AS steal is known to hold acute edges very well. Whether you're sharpening freehand or on some sort of jig, just go for a 5-7 degrees on either side. It's really up to you and your (developing) preferences to decide whether or not you want to add a microbevel to that.
Screaming sharp - no microbevel
Longer-lasting edge - yes microbevel.

I hope this helps,
Dan

Thanks, Dan

This definitely helped me. I will try to re-sharp this knife (for my wife) with 10 degree (per side) micro bevel finished with about 16000 grit. And when I will buy a new such toy for myself then I will try to sharp it without a microbevel at 5-7 degrees and also at 8000 to 16000 grit.


Valery

[Altadan]

I think you've got it

How does your lady fare with carbon steel? Is she happy to deal with the wiping and drying?
I know mine doesn't

Also, the finish is, of course, a matter of preference. I'll just note that I've found that my knives cut everything we eat (from tomatoes, to onions, to bell-peppers, and squashes, and everything else) really nicely in the 3,000-4,000 grit range.
My wife's VG1 santoku is finished at 2,000, and the edge is admirable at almost everything.

Glad to help!
Enjoy the forum for all it's got to offer
Dan

[ValeryD]

I think you've got it

How does your lady fare with carbon steel? Is she happy to deal with the wiping and drying?
I know mine doesn't

Also, the finish is, of course, a matter of preference. I'll just note that I've found that my knives cut everything we eat (from tomatoes, to onions, to bell-peppers, and squashes, and everything else) really nicely in the 3,000-4,000 grit range.
My wife's VG1 santoku is finished at 2,000, and the edge is admirable at almost everything.

Glad to help!
Enjoy the forum for all it's got to offer
Dan

Dan,

To my surprise, she loves this Morutaka AS Santoku 170mm and she cares it with no problem at all. More so, she loves it same as her first japanese knife - Shun 5,5" Hiro SG2 Santoku. And she even likes the blue-purple patina on it! She has never met and owned such a lightweight, perfectly balanced and brutally looking knife.
This story started from here: https://www.youtube.com/watch?v=xXjSN6JDWtk when we both watched Youtube - learning the cutting technique.

I told her about your clear explanation and she takes the decision: I will need to re-sharp the knife with micro bevel at 9.5 degree per side and if it will be still not as sharp as she expects, then I will need to sharp the knife with just 5 degree per side without any micro bevel.

BTW This forum is the best I was able to find so far.


Valery.

[Cigarguy]

I will need to re-sharp the knife with micro bevel at 9.5 degree per side and if it will be still not as sharp as she dreamed of, then I will sharp the knife with just 5 degree per side without any micro bevel.

Yeah carbon steel and Japanese knives are addictive. Not just in using it but also in sharpening too.

Having said that, very few man or machine are able to hold an angle precisely 9.5 degree for the entire length of the blade consistently with every stroke.

I myself can only manage 9.539248423 degree +/- 5 degrees due to age and having flexible muscles and non-rigid joints.

[salemj]

Just to add in another note about these knives: another forum member actually took a couple of his Moritaka knives down to zero grinds. The steel was tough enough that it seemed to hold the edges just fine, and he felt there was real performance improvement.

I wouldn't recommend you do such a thing at all. But I do think you can easily experiment with 10 degrees or less for fun, and you can also probably experiment with a bit of thinning behind the edge to go along with it.

As mentioned above, I also don't really "sharpen" beyond mid-grits for most of my kitchen knives. I usually "finish" them on a slightly higher grit stone or a strop, but that is limited to a few strokes (my current finishing stone is a Japanese natural that leaves a very toothy, mid-grit feeling edge that also has quite a bit of refinement...if I used a synthetic, I'd probably aim for 3-5k for most of my knives, but I've stopped as low as 1.5k many times for use-specific knives). Different people have vastly different preferences in this regard, but just remember that, in terms of cutting actual food, "sharp" is not really determined by how high you go in grits—there are many factors at play. For many people - myself included - I find that very high grit edges often fail to function as well as mid-grit edges over time in my kitchen for most steels, and I particularly enjoy AS steel at slightly lower grits because it is so alloyed that it holds an insanely toothy that is just demolishes vegetable skins of any type with a 2-4k finish.

[ValeryD]

Just to add in another note about these knives: another forum member actually took a couple of his Moritaka knives down to zero grinds. The steel was tough enough that it seemed to hold the edges just fine, and he felt there was real performance improvement.

I wouldn't recommend you do such a thing at all. But I do think you can easily experiment with 10 degrees or less for fun, and you can also probably experiment with a bit of thinning behind the edge to go along with it.

This is a very interesting info. Thanks.

Will see if this possible to thin the blade right behind the cutting edge. I have zero experience in sharpening such knives with HRC 60-65 while I have a huge experience in grinding, polishing and figuring of optics. Should not be too much difference except the geometry. For the first time I'd better ask a man who sharpens knives on a regular basis.


Valery