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Oct 11, 2009 09:47 AM

Sharpening a masamoto gyutou 8.2 inchs

This is a japenese hybred and has 15 degree angle on both sides. I don't know if there is a good electric sharpener out that can maintain it's sharppness. It is fairly pricey so if I can't maintain it's orginal condition it might not be worth.

I do sharpen knives by hand but only western 20 degree knives. A 15 degree VG-10 might be tricky. Maybe I am making more out of this than is necessry but it would really be bummer if it became no sharper than my western knives.

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  1. If you insist on electric, Chef's Choice makes a model specifically for asian knives. They also make an 'Angle-Select" or "Edge-Select" model that has both 20 and 15 degree sharpening angles.

    1. I don't really recommend the electric, even if it is at the correct angle. Electrics tend to have problems on hard, "chippy" knives, and while VG-10 isn't too extreme, it's still hard enough to be a problem. Even more to the point, what's the use of a nice, high-performance Japanese knife if you're gonna treat the edge just like you would a wusthof? Electrics don't create the type of edge that knife is capable of taking. And that knife wants a nice sharp edge.

      Obviously, that's all beside the point if you can't hand sharpen. But since you can sharpen at 20 degrees, trust me that you can sharpen at 15. Much like 20, only lower. How do you normally hand sharpen? When you start, do you measure the angle out? Or find the cutting edge? Or find the large secondary bevel and then finish with a microbevel (or not, depending)? What type of abrasive do you sharpen on? Your technique can easily be adapted in any case, but I'd need to know what that technique is to help you further.

      46 Replies
      1. re: cowboyardee

        Excellent advice, I concur. You know your stuff. Would a tri stone be suitable?

        1. re: bushwickgirl

          A tri stone can get you admirable results.

          I personally prefer a series of individual synthetic waterstones, but if you already have the tri stone (like a norton model?) I wouldn't sweat it.

        2. re: cowboyardee

          I use Waterstone combination grit stones made by Norton. These are wet stones.

          I keep my knifes pretty sharp. But I fear to keep my masamoto perfect I would have to be perfect. I fear just being good isn't enough here. I read that the heal of the knife should be two pennies high according to the sharpening literature at I might buy aForschoer Victorinox and practice. It is a good knife hybrid but not a high end knife.

          1. re: cowboyardee

            I guess what I am saying is I am ok maybe even good. But the question is if I buy a world class knife with a world class edge can I keep it that way.

            1. re: wdames

              There are expensive Japanese knives that require altered or specialized sharpening techniques - single bevel knives or some of the super thin and acute gyutos (suisin inox honyaki, for example). Fortunately, the Masamoto vg-10 is not one of them. Skill + nortons should be plenty to put a very perfectly good edge on that knife. And because the geometry is fairly conventional, any mistakes you make in your early attempts can be easily fixed once you're more skilled.

              So yeah, if you buy a masamoto, you can keep an edge worthy of the knife.

              I don't really like advice along the "2-pennies" line because it's confusing - just take from it that the spine of the knife shouldn't be very high off the stones. Chem's advice is much more useful. Check your progress often. If you're not well practiced at visually confirming your progress, you can try the magic marker trick: color the edge with a magic marker and then make a couple passes on a norton stone. If you have the correct angle, the marker will be evenly abraded away. If your angle was too high, the marker will be worn away only near the extreme edge; too low and it will be worn away only near the top of the bevel. A magnifying glass is useful. And take your time.

              Practicing on another knife is useful, if for no other reason than because it will keep you from putting too much wear on the masamoto while you improve your skills. And forschners are good because they're actually useful as knives in addition to sharpening practice.

              A few other options - no one's mentioned it, but if you're really concerned, you could get yourself an edgepro. A bit pricey, but there's no guesswork - you WILL get a pristine edge, every time. I've even heard of people making their own edgepro-like gizmos for, like, $50. If you're a good hand sharpener already, I'd recommend you stay with that, but the edgepro is a nice nuclear option.

              I f you're still unsure of yourself, to buy yourself some time, you also might want to consider sending the masamoto out to a pro the first time it needs sharpening - MUST be a pro that sharpens by hand and is well versed in Japanese knives. If you find the right guy, he won't be cheap - if he charges $5/knife, i can almost guarantee you he's using a chef's choice or something similar. The upside of forking out for a true pro sharpening is you can get a good idea of what you're aiming at, what your knife is capable of - it will be much nicer than the factory edge. If at all possible, i recommend this guy:

              1. re: cowboyardee

                Thanks alot for advice and confidence builder. I will try your magic marker trick. I just bought the knife for about 80 with tax which is a good deal because it is out there for over 150. I should have it three days and can't wait to get chopping.

                1. re: wdames

                  Do tell, where did you get it for $80?

                  1. re: bogie

                    Thanks for the question! I bought a similar knife but I noticed it didn't say VG-10. I called Koran knifes and sure enough it was a different knife so I stopped the order and ordered the right knife. The really bad news for me is I will not get it until the last week in January for about $130. I could get the next larger sized but I think it would be to large. I have a 10 1/2 inchFprschner and a 9 and something inch sabatier and I prefer my 8 inch plus knife for ease of use. So I guess I will have to wait for the knife of my dreams.

                    I am going to inexpensive Victorinox by Forschner * inch which will give practice at sharpening a 15 degree angle. Never have to many knifes :-)

                    1. re: wdames

                      I agree with Scubadoo here and like to reiterate his points. You won't able to make that perfect 15 or perfect 20 degree edge. The tip of your knife may be 15 and the heel may be 17, but does it really matters? No. In fact, I would say you have a pretty good hand if you can maintain your entire knife within 2 degree.

                      It isn't going to be perfect like some people think. I don't.

                      It is, however, going to be better than using a dull knife and sending out to random knife sharpers. Knife shaprners will charge you what? $20-30 per knife maybe? Someone correct me here, please. So if you think you will sharp more than six times in your lifetime, then you may as well do it yourself. I think a bread knife is a different matter because of the serrated edge.

                      I think you need to look at your knife and see if they are easy for you to sharp. In my opinion, the full bolster knives can be difficult to deal with because the bolsters go all the way down to the heel:


                  2. re: wdames

                    Yes don't be afraid of sharpening your Japanese knives. Sure you won't do it like a pro and you may get some scratches on your knife that don't look great but scratches happen to even the pros. They just polish them out when they are done. You may not be able to maintain the exact geometry and edge symmetry but you will be far better off maintaining your knife and learning to sharpen it at home than sending it out a couple of times a year and using a duller knife for the majority of the time.

              2. re: cowboyardee

                Cowboyardee, you seem to know a lot about knives. I am a complete novice when it comes to sharpening. I recently bought the Masamoto Gyuto 8.2" and I, like the OP, was also wondering about sharpening as well as about the edge.

                I noticed that one side of the blade has a smooth, shiny edge and the other what looks like a regular edge. I thought that Gyuto knives had 15 degree edges on both sides? So does the smooth, shiny edge have nothing to do with this? Should the blade be sharpened on both sides?

                I sharpen my Western knives with a Chef's Choice 130 electric sharpener. I was considering purchasing a Chef's Choice 463 Manual Asian Knife sharpener, as I only have one Japanese knife. I have no idea how to use a whetstone, so I need some advice. The Chef's Choice 463 is recommended by Cook's Illustrated, which is where I learned about the Masamoto in the first place.

                What do you think?

                1. re: chefhound


                  The OP is about a hybrid (Japanese/Western) knife. Yours is purely Japanese. A real Gyuto is single bevel only. For these knives, you definitely have to sharp by hand. Congratulation on your Masamoto Gyuto.

                  1. re: chefhound

                    Which Masamoto series do you have? If It's a gyuto with a western handle I suspect you have a asymmetric bevel (more pronounced on one side than the other) and not a true single bevel edge. It could be something around 80/20, 80% on the front of the knife and 20% on the back. If you are right handed the front is to your right.

                    If the idea of using a whetstone is daunting you many want to consider the EdgePro Apex guide system. A little pricy but you will be able to sharpen all of your knives and have excellent control of the bevel angle. A short learning curve but you will be turning out spectacularly sharp edges on your first try or shortly after.

                      1. re: chefhound

                        Does your knife have a western style handle or the Japanese magnolia wooden handle with water Buffalo Horn bolster? The western Masamoto that is now listed as a VG. Seems there is no cobalt in the steel so it is in fact not VG-10. They have just posted this change in descripton.


                        Again if it's the western variety then i'm pretty sure it is double beveled but as is typical it's very asymmetric. You just need to do more passes on the wider side to keep it that way. I have a honesuki which has something like a 90/10 or a 95/5 asymmetric grind. Looks like a single bevel knive but the flat side is not hollow ground and has a very small bevel.

                        1. re: scubadoo97

                          I have the western handle and the Hyper Molybdenum Vanadium blade. I've never had an asymmetrical blade before and it confused me. Thanks for the info - very helpful.

                      2. re: scubadoo97

                        I bought the same knife but will not get mine until late January or early Febuary so I am a little envious :). It was explained to me that it is a western hybrid with a 15 degree angle on each side. I also bought the Forscher 8" victorinox to practice for under $30. I use whet stones for my western knives and am ok at it. What intiminates me is how sharp my Japenese knives are. The fear is can I keep them that way. I hope so. Cowboyardee posts are quite useful.

                        1. re: wdames

                          I think a lot of people are afraid of just that - that they won't be able to put as nice an edge on their knives free handing as the one it came with. Think of it this way - with only a solid understanding of your knife's geometry, the magic marker trick I mentioned above, and barely minimal experience with free handing (we're talking just a couple tries), you will be able to get at least as good an edge free handing as you would with one of the gizmos (the edgepro system aside).

                          The learning curve is weird. I think I am pretty typical. My first couple attempts free handing were not impressive, but they weren't disastrous either. I learned to get a pretty good edge shortly afterward. It just took A LOT of work each time. And as I've gotten better, I've found that it just takes me much less time to get good results - less wasted effort, fewer scuff marks on the side of the knife, less second guessing, neater bevels. But it was already a useful skill within my first few attempts.

                          And the really cool thing about a lot of these Japanese knives that are so sharp that they make you second guess your skills? A lot of them seem to WANT to be sharp. It's not that the guys doing the sharpening in Japan are more skilled than the ones in Germany. It's that the knives themselves are more willing to take and hold an extremely fine edge because of how they're made. I think you'll be happily surprised with where the skills you already have can take you.

                      3. re: chefhound

                        There are very few single bevel gyutos out there. I wasn't aware of Masamoto making one, but I always could be wrong. Or if you bought it used, whoever you bought it from could have done God knows what with the geometry. If you''re curious, just lay the smooth side of the knife on a flat surface with the handle and bolster hanging off - like on the edge of a counter. On a single beveled knife, both the spine and the edge would be completely flush to the flat surface. If it's not flush, it's not single beveled. If it actually is single beveled, what I'm about to say won't apply, and yes, you will need a stone and some technique.

                        Far more likely, you've got an asymmetrical edge. This is supposed to reduce resistance and improve performance slightly by making the area behind the edge thinner without sacrificing edge durability. Most people who buy a nice knife for the first time are very concerned about preserving that knife's geometry. If you're sharpening by hand, this is not really any harder than preserving the geometry on a symmetrical beveled knife - just find the edge angles and sharpen at them.

                        Here's the (or one) problem with something like a chef's choice - in some cases these asymmetrical edges are ground at the same angle on each side, but in many cases they aren't. A chef's choice will of course grind at the same angle on both sides. Also, to maintain the geometry, the larger bevel (probably on the right) will wind up needing slightly more sharpening that the smaller one (left.) *Note to fellow nerds- this is not because you want to work the large side harder, but simply because a larger surface needs more abrasion to achieve the same amount of work.*

                        Try the following - again lay your knife on a flat surface - this time something you can cut into a bit - hard leather, wood, plastic - as long as it's flat, soft enough to cut into and doesn't have much give. Very, very slowly raise the spine of the knife while slowly pushing the edge forward. When the edge catches, look at how high the spine is - that's your edge angle. Do this for both sides of your knife. (Note that this is the angle for the actual edge only - not a secondary bevel.) You now know roughly whether both sides are ground at the same angle. If they are, a roller sharpener (the chef's choice) set at the correct angle would preserve your geometry for a while.

                        The thing is - preserving the edge EXACTLY isn't necessary. A degree or two of wiggle room is fine - even great free handers aren't perfectly precise. What matters is that your geometry is good - that you keep it thin behind the edge, that your edge itself is both sharp and true, that your edge angles make sense for the knife. And here lies the limitations of a roller sharpener - it produces a mediocre edge that is neither all that sharp nor all that strong, it doesn't thin behind the edge at all, and it does not give you any angle control -- if one bevel of an asymmetrical knife is greater than 15 degrees (in this case), it won't hit the edge from that side at all until you've essentially reprofiled it. And reprofiling a hard Japanese knife with a dinky roller sharpener does not sound like my idea of a good time.

                        Of course, the roller sharpener would be better than not sharpening at all. I just can't recommend it very highly. If neither side of the masamoto is over 15 degrees, it would be at least somewhat effective at sharpening. In any case it wouldn't ruin the knife, just slowly alter the geometry.

                        Other options? Free handing is not as hard as it's made out to be - remember that you are essentially just rubbing a piece of metal on a rock until it's pointy. A caveman could do it. And it doesn't have to be expensive. Also, the edge pro system is fantastic (it seems like I can recommend it until I'm blue in the face but no one who wasn't already inclined to get one ever does). Some people really love the Spyderico Sharpmaker, but I have no experience with it. Finally, a professional is a great option, but you might really have look around to find a good one - find someone willing to forgo a belt sander and be willing to pay for his premium package.

                        Sorry if any of this got hard to follow - just got off a long day at work. But if you need clarification, I'll happily provide it.

                        1. re: cowboyardee

                          Thanks for taking the time for such a detailed reply. I really appreciate it. I will try what you suggest to determine the edge. And I will look into the Edge Pro. I'm just learning about knives and I want to keep mine in good condition.

                          1. re: chefhound

                            I took your advice, cowboyardee and I looked into the Edgepro Apex. The video was great and it was obvious even a complete novice like me would be able to do it.
                            I just got it yesterday and I can't wait to try it on the weekend. I'm going to practice first on my Forschner to get feel for how the whole system works. It should be pretty straightforward. I set the machine to 20 degrees and I make the same number of passes on each side until I feel the burr. But I need help with the Japanese edge.

                            I've determined that my Masamoto gyuto has a double-beveled asymmetrical edge. So this is what I need to know:

                            1) How do I figure out if it's 80/20, 70/30 or what the actual symmetry is or is that even important?
                            2) So if it's 70/30, I make 7 passes on one side for every 3 passes on the other? Is that how it works? And I repeat this until I feel the burr?

                            Any advice would be greatly appreciated.

                            1. re: chefhound

                              remember that 80/20 means that the bevel is 80% wide on one side and 20 on the other. It says nothing about the actual angles. Once the bevels are cut in I think you can do equal passes on each side. I could be wrong so anyone with expert knowledge correct me if this is not correct.

                              To check the angle use the shapre technique to see where metal is being removed.

                              1. re: scubadoo97

                                As I understand it, Japanese knives have a 15 degree angle. So would set my Edgepro to 15 degrees and then make 7 passes on one side and then 3 passes on the other, or 8 and 2 depending on what the actual bevel is, right? And repeat until the burr is achieved?

                                1. re: chefhound

                                  Hi Chefhound,

                                  I think what scubadoo means is that there are two different types of a 70/30 -- actually more than two. You can have a double bevel 15o each side, but one side ground more, thus the 70/30 and you can recreate that edge using the method you mentioned. Or the two side is not same in angle. You can have one side in a 22 degree and the other side a 8 degree, which will still give you a total 30 included angle. In this case, you will grind them with even pass. (some one check my math here please)

                                  1. re: Chemicalkinetics

                                    Boy, this is getting complicated - and I was never any good at math! Can I just color in the bevel with marker and if I remove all the marker evenly, I've matched the original degree?

                                    1. re: chefhound


                                      Sure. The color marker definifely works. But here is a chance for you to put a new edge especially with a precision tool like this one. Who knows, maybe you like a 50/50 better.

                                      1. re: chefhound

                                        Sure. The magic marker method will work. On the other hand, this is a really good opportunity to put on a new edge if you like, especially with a precision tool like this one. Maybe you will work better with a 50/50 better.

                                        1. re: chefhound

                                          Start out trying to preserve the original angles if you can. No big harm done if you change it. But see how you like it with the original bevels. I took my 270mm sujihiki slicer and changed it from a 50/50 symmetrical beveled edge to a 80/20 asymmetrical edge after using it for some time. This made the edge even thinner and it cuts more like a yanagi. No it's not a yanagi but it can slice fish paper thin, tomatoes that are see thru and then cut pastrami or a flank steak.

                                          1. re: scubadoo97

                                            I liked how it works with the original bevels and I think I will keep them for now. I'll wait until I become more experienced at sharpening before I attempt changing anything - though I would like to slice see-through tomatoes!

                                            So how do I determine if my knife is 70/30 or 80/20 and how much is on each side?

                                            1. re: chefhound

                                              chefhound, take a look at these post over at

                                              The first two sets of pictures are sure to confuse the heck out of you.

                                              A nice discussion of the subject. Pay attention to D R Sharpening's thoughts on both post discussions. That's Dave Martell who is one of the best J- knife sharpening guys in the US. The post is from '05 so many of these people who are now quite experienced were just getting a handle on it then.


                                                1. re: scubadoo97

                                                  I can't thank you enough! It's all starting to make sense to me, finally!

                                                  It's going to take some time to process all this information but I'm finally starting to get it. When I bought my knife, I just wanted a really good knife. I had no idea I would have to learn so much about knives and angles and stuff. Or that there would be so much to learn.

                                                  As for the questions, I'll have to read these discussions over a few more times and after I've attempted to sharpen my knife, I'll get back to you.

                                                  1. re: chefhound

                                                    I just wanted to report back on the status of my Masamoto Gyuto.

                                                    I got in touch with Ben Dale, the creator of the EdgePro sharpening system. I wanted some tips before I attempted my gyuto. He told me that he has sharpened lots of Misono knives but never a Masamoto. He offered to sharpen it for me and give me detailed instructions on how to use my EdgePro Apex to do it for myself.

                                                    So I sent my knife to him and just got it back. He did a great job and was very helpful. He was very impressed with the knife and said it was better than any of the Misono and Shun knives he has sharpened.

                                                    I missed my knife while he had it. After using a Japanese knife, all my other knives seem somehow clumsier, less refined. Great, now I'm going to have to buy more Japanese knives! My wallet is not going to like it!

                                                    1. re: chefhound

                                                      And so it begins.

                                                      I'm curious what tips Ben Dale gave you. He would know the ins and outs of the edgepro pretty damn well.

                                                      I like that you sent it out to a pro once. I think most people interested in sharpening at home (on stones, edgepro, spyderco, etc) should do exactly that. A pro will leave you nice, flat, even bevels that are easy to work with and will also give you a really good idea of what you're aiming for. Its hard to go back to using a mediocre edge after you've used a fine knife sharpened by someone who really knows what they're doing.

                                                      Thanks for updating with your experience so far. I hope that Masamoto provides you with decades of enjoyable use.

                                                      1. re: chefhound

                                                        My wallet will like it just fine. It is your significant other won't like it.

                                                        1. re: chefhound

                                                          Thanks for the update. Ben is a great guy and any tip he can give you on how to use his invention is golden. There's no turning back now that you know what sharp is

                                                          1. re: chefhound

                                                            Ooh, I have the exact same knife and have been researching how to sharpen this guy as well. +1 for sharing whatever tips and advice Ben may have shared!

                                                            1. re: PlutosRevenge

                                                              I've been meaning to respond but I've been so busy, there just hasn't been any time.
                                                              The tips he gave me were for my knife specifically. After he sharpened my knife, all I need to do to maintain it is to use the 1000 stone and the 3000 polish tape.
                                                              Ben told me that my knife went from 17 degrees at the back to 7 degrees at the tip on the side with the main bevel. He said that nothing can hold a 7 degree angle and that's why there were small chips on the edge. So he straightened it out for me and now all I have to do is maintain it.

                                                              You should get it professionally sharpened once and then all you have to do is maintain it. But be sure it's a reputable sharpener who knows Japanese knives and doesn't use an electric sharpener.

                                                              1. re: chefhound

                                                                Wow, what a difference in angles. I bet you were wondering why you couldn't raise a burr near the tip.

                                                                1. re: scubadoo97

                                                                  Actually, I never sharpened it myself. I purchased my knife from a guy on Ebay and just used it as it came. I was afraid to sharpen it myself, which is why I asked Ben for some tips. Thankfully, he offered to sharpen it for me.

                                                                  I will be making my first attempt to sharpen it myself sometime in the future but not anytime soon. Ben's sharpening job should last me a while.

                                                                2. re: chefhound

                                                                  7 degree. I see you are a very ambitious man.


                                                                  Actually, I made the same mistake on my usuba. For some reason, the tip (a rounded tip nevertheless) is at a lower angle and chips all the time. I have to intentionally put a second bevel on it.

                                                                  1. re: chefhound

                                                                    This post is almost a year old, but I wonder if I could revive it. Chefhound (or anyone else that has tried this), have you had any luck sharpening your Masamoto on the Edge Pro with a 17 degree angle at the back and 7 at the tip? Have you felt that these were an accurate description of the factory angles? And, if so, at what part of the knife did you have to change the angle? Only once you got to the tip, or closer to the middle? Thanks in advance.

                                                                    1. re: dannynyc

                                                                      I've sharpened an inch or two at the heel of a knife to a steeper angle than the rest of the knife - can be useful to make an otherwise thin, fragile knife suitable for also cutting light chicken bones and other iffy things. Worked fine, though you have to be careful to keep the edge straight when you do this (if you're adding a more obtuse section, make it only a microbevel or the edge will retreat; if you're adding more acute section, there's less to worry about, though it can take a while). This is often done with yanagibas. I did it with a couple gyutos and also with my honesuki.

                                        2. re: cowboyardee

                                          I use the technique you described above to check my angle for stropping. I will also use this technique on my wood cutting board to find the angle and to set my hand memory when moving to the stone. Slide and raise until it first bites.

                                          1. re: scubadoo97

                                            I got my virgin carbon masamoto last week, it wasn't really sharp out of the box like kanetsugu. the reason i bought it because i do a lot of cutting (thin hair) everyday, with kanetsugu i have to sharpen it almost everyday with kingstone 6000 (just for minutes) and i hope with this one i don't need to do it everyday. I tried to cut with this knife but wasn't really satisfy with the result, i did better with my victorinox so i changed the angle to 7-8 degree (like all of my gyuto and santoku) one side only . Now it's is very2 sharp and this knife can keep the edge for few days.
                                            I know most of u guys won't agree with this angle but i think this is the best for me, it suit my style and need. So don't be affraid if u make mistake, just practice with cheap knife, buy a wetstone 1200 grid will be enough. As long as u keep the angle steady you won't ruin your knife.

                                            1. re: sushigila

                                              By making your edges asymmetric you have effectively thinned the knife behind the cutting edge. I've done with with my sujihiki which bumped up the sharpness factor and it's great for slicing raw fish and making very thin slices. Not as good as a yanagi but works for me.

                                    2. Wdames,

                                      No doubt cowboyardee knows his stuffs. Definitely hand sharp your knife. If you worry, try to practice the 15 degree on a very cheap knife. The only additional advise I have is to start grounding slow. Instead of sharping your knife for five minutes and check your edge, try to check your progress more often. This will prevent you grind the knife at the wrong angle for too long.

                                      1. The original comment has been removed
                                        1. No, good electric sharpener is an oxymoron. Also an electric sharpener even at the correct angle would ruin the edge on VG-10 steel. Either take it to a professional, or learn how to sharpen it on your own. The Mino Sharp series of water stones come with little widgets to help you maintain a perfect 15 degree angle while sharpening and the extra fine stone will but a wicked sharp edge on your blade.

                                          2 Replies
                                          1. re: brad87561

                                            Why would an electric sharpener at the correct angle would ruin the edge? Is it because it is too fast, so the edge will be heated to high and ruin the steel tempering? If that is the case, one can always be more caution and dip the knife into water between sharpening run on an electric sharpener.

                                            1. re: Chemicalkinetics

                                              heat, is a yes. Vibration is also an issue as it can cause the blade to chip in the sharpening and/or weaken it and make it prone to a future chipping.