Japanese Knives: The Big Topic

[dougal]

Mine arrived today.

Beautiful.

And sharp.

Its not at all heavy, but, out of the box, it will ever-so-nearly slice carrot under its own weight.

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Hi can I confirm that you bought the SANETU ZDP189? I have been eyeing that knive but haven't quite taken the plunge yet. I look forward to hearing your views on whether its worth its price. How does does its edge retention properties sit with ease of sharpening?

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Yes, that's the knife.

Comparative value? No idea, yet. Out of the box its the sharpest knife I've ever used. Its price translates to within a few beers of Amazon UK's price for a fluted Global Santoku.

Which makes it seem like a mega-bargain compared to any other kitchen knife in Cowry or ZDP.

Not Champagne on a beer budget, but something better than First on a Business Class ticket.

But its still the most expensive knife I've bought. *

I have no idea (and don't plan on immediately discovering) how difficult it is going to be to sharpen to an equivalent or better edge.

As yet I've no idea how long it will actually hold this edge in my light home use.

I regard it as an opportunity to 'calibrate' my own opinions, in an area far outside my normal experience.

I hope I remain awed (and slightly scared) by it...

I'm not a knife nut (yet).

* So far...

[Patapsco Mike]

I bought a ZDP189 knife two years ago, and learned the hard way that this steel is extremely prone to rusting and pitting. Worse than any other knife I've ever owned, including old high carbon non-stainless knives. I suspect this is why they don't want you to cut pineapple- I bet the corrosion will be just about instant. If you leave these knives wet for any length of time you will find surface corrosion.

Those with ZDP189 knives who don't want visible streaks on the blade will need to take care not to cut anything that is acidic. Don't believe me? Put a couple drops of lemon juice on the blade and leave it there for 5 minutes. Wash it off and you'll see the steel is already discolored.

I returned my knife, and will never own another ZDP189 blade. I have enough high maintenance things in my life... There are other true stainless steels out there that perform about the same with no maintenance issues. I ordered a S30V blade to replace it, and have been in high cotton ever since.

Edited to add- whoa- they advertise these on their site as "rust proof" in the next sentence after they say "high carbon." That's a bit like saying "creamy, succulent AND low fat."

Edited December 14, 2007 by Patapsco Mike (log)

[Octaveman]

ZDP189 is like any other stainless knife...rust and stain "resistant", not 100% stainless. I've had VG10 knives stain and actually rusted when my wife left the knife in a glass of water to soften the dried on food from her use. Pissed off to say the least. Point is that reasonable care should be made when using. Cut something acidic? Rinse it off when your done.

Regarding the rust proof claim on JCK's site. Lets not forget that we are dealing with Japanese people who do know the english language but there are subtle differences in translation/understanding that do not come across correctly. The "pumpkin" mentioned above is one example. If you look hard enough, you will find other inconsistancies but the intent is never to deceive the visitor.

Dougal, I really don't think it will be that hard to sharpen. If you do regular touch-ups and don't LET it get dull, then it won't be a tough job to sharpen it. When it comes time to thin it though....good luck.

[Patapsco Mike]

ZDP189 is like any other stainless knife...rust and stain "resistant", not 100% stainless.

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I agree that no stainless (except H1) is completely rustproof, but based on my personal experience and that of other knife nuts I think you'll find that ZDP189 is far more prone to both surface rust and pitting than any of the normal stainless steels used in high end kitchen cutlery (e.g. 440 a and c, VG10, and S30V).

I also strongly suspect this is why they don't want you cutting pineapple. Try the lemon juice test and see...

[Fugu]

Although JCK does not mention it on their website, the ZDP-189 being offered is clad in ATS-34 stainless and is supposed to be more rust resistant than the ZDP-189. Here http://www.foodieforums.com/vbulletin/showthread.php?t=1361

Edited December 16, 2007 by Fugu (log)

[dougal]

I agree that no stainless (except H1) is completely rustproof, but based on my personal experience and that of other knife nuts I think you'll find that ZDP189 is far more prone to both surface rust and pitting than any of the normal stainless steels used in high end kitchen cutlery (e.g. 440 a and c, VG10, and S30V). 

... Try the lemon juice test and see...

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I did (on the JCK Sanetu ZDP189 Santoku).

10 minutes.

No marking whatsoever on the side of the knife. (Where I put the juice drops.)

Whatever the effect might be on the exposed cutting blade of the magic stuff, the stainless cladding is just as mirror-pretty as before...

Phew!

[Patapsco Mike]

I'm sorry if I wasn't clear in my posts. It's ZDP189 that is prone to corrosion, not the ATS-34 on the sides. The sides of these knives should be worry free. It's the core of the knife that is of concern (i.e. the part that does the actual cutting).

It seems that practically all the makers of ZDP189 blades are aware of the rust issue. These knives are all being offered now either clad in a more stainless steel or with a durable coating on the blade. Such knives will stay nice and pretty even if the edge rusts away...

Try the lemon test on the ZDP189 part, if you dare.

[dougal]

...

Try the lemon test on the ZDP189 part, if you dare.

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In my case, no way until after I have adequate sharpening technology in place to re-dress things.

And a microscope, and a few control knives for comparison...

I wouldn't ordinarily leave anything acid on any knife for any length of time.

I would expect *any* clad knife to tend to have more corrosion problems than a knife of uniform composition.

Where you have two dissimilar metals, in electrical contact and both in contact with an electrolyte, you have an electrochemical corrosion cell. The cell voltage (influencing corrosion rate) depends on the difference between the two metals "electrochemical potential". And IIRC even different heat treatments (and different mechanical working) can give rise to different potentials.

From what I know of why lightening conductors work (increased charge density at the sharp point), I'd expect any corrosion of any clad knife to be most evident on the sharpened edge, because it is an electro chemical process, and that's where the field would be strongest, ion transport easiest, etc.

I don't believe I have any other clad knives to compare it with, to see whether the effect is distinctly worse with ZDP189.

However, I do recall the lore that Tomato blunts knives disproportionately quickly. My suspicion has been that that this was due to the acidity of the tomato, rather than any great toughness of the skin. And the lore dates from the time when all good knives were "steel" (not stainless).

I'm enjoying using this knife. It goes through onion and carrot... well... "like a knife through butter". Now, while I know this is largely a sharpening thing, my hope and expectation is that this knife will hold this extreme edge way better than something more traditional.

And for that, I'm prepared to nanny it a bit.

[Patapsco Mike]

As a scientist and owner of one boat (and responsible for four work boats) used and sometimes left in saltwater I am painfully aware of galvanic corrosion. However, in knives this is not a problem. In fact, the cladding is typically used to prevent corrosion and discoloring (and/or to add toughness).

I'm sounding like a broken record, so I'll stop. I wish you luck. So long as you do some light oiling after using the knife, you will probably end up loving the incredible wear resistance of ZDP189.

[dougal]

Thanks Mike and thanks for the warning!

To just nail this (hopefully finally)

... I am painfully aware of galvanic corrosion.  However, in knives this is not a problem.  In fact, the cladding is typically used to prevent corrosion and discoloring (and/or to add toughness). 

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Yes, aware of the toughness and cosmetic (perhaps frictional) reasons for the cladding.

My point was that corrosion will be focussed at the sharp edge of the blade, and the sharper the blade, the more the edge would be subject to attack.

Secondly, for a corrosion cell, you ideally need two dissimilar metals - and in that respect the cladding could actually exacerbate the problem.

This thing has a pretty acute edge (anyone measured the angle yet?) - so with the cladding layer to provide the second electrode there exists considerable 'potential' ( ) for corrosive dulling of the edge.

It may even be that this, rather than wear, will determine the need for resharpening.

In the meantime, I'll treat it kindly!

As a final point, the strange "no pumpkin or pineapple" leaflet appears to be general guidance from JCK rather than being specific to ZDP189.

[paulraphael]

I'd like to hear from a metalurgist on this, but my impression is that clad metals don't present any galvanic corosion issue. You need more than just two "dissimilar" metals. They need to be dissimilar in a way that one behaves like an anion or cation relative to the other, and you need some kind of electrolite between them.

When you have this kind of condition, the whole assembly turns into a battery, and the metals deteriorate pretty quickly. I remember this being an issue with some early generation carbon fiber bicycles, that were made by gluing carbon fiber tubes into aluminum lugs. There's a relative charge between the carbon and the aluminum, and the epoxy being used functioned perfectly as an electrolyte. The bikes performed beautifully, and then in a few weeks spontaneously fell apart.

Kasumi style knives, with various kinds of stainless and carbon steels clad in various kinds of iron and other stainless steels, have been around for a long time. And if there were issues with galvanic corrosion, you'd expect to see it between the clad layers, resulting in the knives delaminating. I wouldn't expect it to express itself as rust on the cutting edge.

[Octaveman]

Do you people honeslty think that a carbon steel knives wears down so fast that you have to be so protective of it? Oil it every day? Edge rusting away? Do you think those 40-50 year old carbon knives never touched acid in foods? I only have two SS knives in the bunch and all my carbon knives have NEVER formed any rust and no oil was ever applied. Applying oil does not extend the life of your knife. Unless you sharpen it down to nothing your knife will be here long after you're gone.

These knives are not left in salt water 24/7 and dissimilar blade materials is not the cause of having to sharpen once a month due to corrosion. Good grief. You have to sharpen because you bang your edge against the cutting board, not because your knife was exposed to the volitile combination of food, water and oxygen.

The cladding is put there to support the hardness of the core. Nothing mysterious. The cladding can either be "stainless" or wrought iron depending on what the maker wants to use and the type of knife. The purpose for using a stainless is so the people that freak out because a patina might form on their knife can rest at ease and keep their knife looking pretty. Oh yeah, and it's softer than the core it's surrounding.

[Patapsco Mike]

The cladding is put there to support the hardness of the core.  Nothing mysterious.  The cladding can either be "stainless" or wrought iron depending on what the maker wants to use and the type of knife.  The purpose for using a stainless is so the people that freak out because a patina might form on their knife can rest at ease and keep their knife looking pretty.  Oh yeah, and it's softer than the core it's surrounding.

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It's just not true, in this case, that a softer material is needed to "support the core." I think your second statement is right- it's just to keep the knife pretty.

I agree that the rust is not a huge issue, or that it will appreciably shorten blade life. It's just ugly, and something to keep in mind in terms of not letting the blade sit in the sink or on a damp dishcloth overnight.

[Octaveman]

The cladding is put there to support the hardness of the core.  Nothing mysterious.  The cladding can either be "stainless" or wrought iron depending on what the maker wants to use and the type of knife.  The purpose for using a stainless is so the people that freak out because a patina might form on their knife can rest at ease and keep their knife looking pretty.  Oh yeah, and it's softer than the core it's surrounding.

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It's just not true, in this case, that a softer material is needed to "support the core." I think your second statement is right- it's just to keep the knife pretty.

I agree that the rust is not a huge issue, or that it will appreciably shorten blade life. It's just ugly, and something to keep in mind in terms of not letting the blade sit in the sink or on a damp dishcloth overnight.

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Really? Why are Ryusen Blazen knives San Mai made? Why are Artisan knives San Mai made? Why do you think Ikeda knives are San Mai made? I could go on with a whole slew of knives that have a stainless core that are also stainless clad. Unless the knife is a Honyaki, it would be difficult to find any blade with a high HRC rating that the ZDP189 has that is not surrounded by a softer material for support. Look at all those knives made with tool steels (SRS-15 and the like)...they are ALL clad and they are ALL stainless. Why do you think that is? Even carbon core knives are clad in carbon so what do you think the point of that is if the carbon cladding never becomes part of the edge? It's certainly not there to make the knife look pretty. It's not there because the manufacturers are trying to be inventive. The whole purpose behind this warikomi method of construction is to give strength to a very hard and brittle metal core and this method has been around for a hundreds and hundreds and even more hundreds of years. The only differences between then and now are the materials used.

[Fugu]

I recieved my ZDP-189 along with a Gekko nakiri from JCK yesterday. It took no more than 5 days to get here. No added tax or duty was charged at the post office.

Out of the box, the ZDP-169 and the Gekko nakiri looked like a pieces of jewelry, just beautiful. The Cocobolo wood on the ZDP and the mahogany on the nakiri handle only adds to the beauty of the knives, no burrs, no sharp edges, good for small hands, balance is good as far as Japanese knives go. I put both to work preparing for Sunday brunch with my nephews and my brother. No visible signs of rust or stainning. The Nakiri is sharpest knife I've ever used but the ZDP-189 needs a little time on a stone, this is in contrast to the beautiful Gekko Nakiri's scary sharpness out of the box. Both knives are a work of art and would recommend it them to anyone. I may get another ZDP-189 but it seems that it is sold out again, along with a Hattori wa-gyuto.

[Octaveman]

Cool, Fugu. Good to hear you like the knives. I too love the wood on the Sanetu. Look forward to hear what you think after hitting the stones and using for a spell.

[Patapsco Mike]

The cladding is put there to support the hardness of the core. Nothing mysterious. The cladding can either be "stainless" or wrought iron depending on what the maker wants to use and the type of knife. The purpose for using a stainless is so the people that freak out because a patina might form on their knife can rest at ease and keep their knife looking pretty. Oh yeah, and it's softer than the core it's surrounding.

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Really? Why are Ryusen Blazen knives San Mai made? Why are Artisan knives San Mai made? Why do you think Ikeda knives are San Mai made? I could go on with a whole slew of knives that have a stainless core that are also stainless clad. Unless the knife is a Honyaki, it would be difficult to find any blade with a high HRC rating that the ZDP189 has that is not surrounded by a softer material for support. Look at all those knives made with tool steels (SRS-15 and the like)...they are ALL clad and they are ALL stainless. Why do you think that is? Even carbon core knives are clad in carbon so what do you think the point of that is if the carbon cladding never becomes part of the edge? It's certainly not there to make the knife look pretty. It's not there because the manufacturers are trying to be inventive. The whole purpose behind this warikomi method of construction is to give strength to a very hard and brittle metal core and this method has been around for a hundreds and hundreds and even more hundreds of years. The only differences between then and now are the materials used.

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In some cases, you are right about cladding protecting brittle steels. But as you point out in your last sentence, things are a bit different now. ZDP189 is not brittle like the older carbon steels. There are plenty of non-clad ZDP189 blades on the market despite the fact that this is a relatively new material. Spyderco and Kershaw both mass produce non-clad blades. I owned one myself, which led me to my warnings on this thread.

[Rembrant Wood]

Although JCK does not mention it on their website, the ZDP-189 being offered is clad in ATS-34 stainless and is supposed to be more rust resistant than the ZDP-189. Here http://www.foodieforums.com/vbulletin/showthread.php?t=1361

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The working edge is not protected by cladding. Read Chad Wards tutorial. He's right that acid....Citrus..Jalapenos..onions,can rapidly degrade your very high priced ultra hard edge. Also....the POINT of ultra hard is to get a very thin,acute edge...but Hard = Brittle.

Have a tough Wusthoff or Forschner (generally QUITE stainless) for some things and have the ZDP for others. These "ultra Hard/Sharp" blades are NOT do -it -all,in fact,they are relatively specialized. Further...to get the benefits you need to LEARN sharpening skills....not gizmos and shortcuts....

Edited January 12, 2008 by Rembrant Wood (log)

[Fugu]

The working edge is not protected by cladding.  Read Chad Wards tutorial. He's right that acid....Citrus..Jalapenos..onions,can rapidly degrade your very high priced ultra hard edge. Also....the POINT of ultra hard is to get a very thin,acute edge...but Hard = Brittle.

Have a tough Wusthoff or Forschner (generally QUITE stainless) for some things and have the ZDP for others. These "ultra Hard/Sharp" blades are NOT do -it -all,in fact,they are relatively specialized.  Further...to get the benefits you need to LEARN sharpening skills....not gizmos and shortcuts....

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I suppose this needs to be said since not everyone is a knife nut. I've experienced no degredation on my knives. I've been working with this ZDP 189 along with the Gekko, Masamoto, Hattori, Hiromoto and S1 Nenox, since receiving them before Christmas. The knives have been used to slice, paysanne, micro diced, brunoise, chiffonade, julienne and allumettes, everything from jalapenos to onions, supremes of citrus fruits and even removed parmessan rinds, there are no signs of rust or chips because they are "Hard" and "brittle". Only careless and sloppy cooks have rusty equipment. These are all based on my experience with these knives and not based on an article that someone else wrote.

Edited: to make the response more non Klingon like.

Edited January 14, 2008 by Fugu (log)

[Gourmandolo]

Good morning all !!

I've recently purchased a Misono ux-10 series (Santoku) knife after using a Shun classic series w/ granton edge chef( 8 ") for the last few years.

I was persuaded to try the Misono line and as I wait for my knife I thought I'd poke around to see if anyone has had any experience with Misono.

Being that the knives are of different families or styles (classic chef/santo) I'm moreso looking for a comparison in steels, edge maintainence, and all around performance.

Thanks guys !

[miles717]

Good morning all !!

I've recently purchased a Misono ux-10 series (Santoku) knife after using a Shun classic series w/ granton edge chef( 8 ") for the last few years.

I was persuaded to try the Misono line and as I wait for my knife I thought I'd poke around to see if anyone has had any experience with Misono.

Being that the knives are of different families  or styles (classic chef/santo) I'm moreso looking for a comparison in steels, edge maintainence, and all around performance.

Thanks guys !

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Misono makes a very nice knife. Congratulations on adding one to your kit.

I've never used santoku from Shun or Misono so I can't offer any comparisons with the santoku, but I have a Shun Classic 10" chefs and a Misono Swedish Carbon 21 cm gyutou. I've also used a couple knives from the Misono moly line and have tested out a UX10 24cm gyutou. The Swedish carbon isn't the same steel as is used in the UX10 line but I can offer a few general observations regarding the similarities and differences based on my own experiences.

The Misono knives I've used offer significantly better geometry than the Shun blades and they feature a blade shape which is more French in profile than the German shape used on the Shun chefs knives. The Misono knives feel quite a bit lighter when compared to a similar sized Shun. The fit and finish of both Misono and Shun are well above average. The performance of the steel is quite similar between the VG10 used in the Shun blades and the Swedish carbon used in the Misono, although the Misono carbon blade does require a bit more attention in terms of maintenance. I own another knife from a different maker which reportedly uses the same steel as is used in the UX10 series. If my experience with that knife is any indication, you should expect that it will take and hold a very fine edge for a reasonable length of time and will maintain that edge with minimal upkeep. I find the performance to be fairly comparable to other knives in my kit made from VG10 steel.

Generally, the UX10 line is very well regarded by those who own them. People report that the steel takes a very good edge and keeps it, which is consistent with my own experiences with a knife made from the same steel. I'm sure you'll be quite pleased with the performance of your UX10.

I don't steel my Japanese knives, but use MDF and leather hones charged with diamond and chromium oxide compounds to maintain the edges. I rarely allow the blades get to the point where I really think they need to be honed so I find them quite easy to maintain. How do you typically maintain your knives?

Edited January 29, 2008 by miles717 (log)

[Gourmandolo]

Thanks for your response, Typically, Dependant on use of course I'll usually hone my Shun with the shun steel which I bought with the knife and I'll do this perhaps only once or twice in a week at most.

I'm interested in knowing more about your honing methods for your VG steel knives.

Thanks again...

Good morning all !!

I've recently purchased a Misono ux-10 series (Santoku) knife after using a Shun classic series w/ granton edge chef( 8 ") for the last few years.

I was persuaded to try the Misono line and as I wait for my knife I thought I'd poke around to see if anyone has had any experience with Misono.

Being that the knives are of different families  or styles (classic chef/santo) I'm moreso looking for a comparison in steels, edge maintainence, and all around performance.

Thanks guys !

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Misono makes a very nice knife. Congratulations on adding one to your kit.

I've never used santoku from Shun or Misono so I can't offer any comparisons with the santoku, but I have a Shun Classic 10" chefs and a Misono Swedish Carbon 21 cm gyutou. I've also used a couple knives from the Misono moly line and have tested out a UX10 24cm gyutou. The Swedish carbon isn't the same steel as is used in the UX10 line but I can offer a few general observations regarding the similarities and differences based on my own experiences.

The Misono knives I've used offer significantly better geometry than the Shun blades and they feature a blade shape which is more French in profile than the German shape used on the Shun chefs knives. The Misono knives feel quite a bit lighter when compared to a similar sized Shun. The fit and finish of both Misono and Shun are well above average. The performance of the steel is quite similar between the VG10 used in the Shun blades and the Swedish carbon used in the Misono, although the Misono carbon blade does require a bit more attention in terms of maintenance. I own another knife from a different maker which reportedly uses the same steel as is used in the UX10 series. If my experience with that knife is any indication, you should expect that it will take and hold a very fine edge for a reasonable length of time and will maintain that edge with minimal upkeep. I find the performance to be fairly comparable to other knives in my kit made from VG10 steel.

Generally, the UX10 line is very well regarded by those who own them. People report that the steel takes a very good edge and keeps it, which is consistent with my own experiences with a knife made from the same steel. I'm sure you'll be quite pleased with the performance of your UX10.

I don't steel my Japanese knives, but use MDF and leather hones charged with diamond and chromium oxide compounds to maintain the edges. I rarely allow the blades get to the point where I really think they need to be honed so I find them quite easy to maintain. How do you typically maintain your knives?

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[miles717]

Thanks for your response, Typically, Dependant on use of course I'll usually hone my Shun with the shun steel which I bought with the knife and I'll do this perhaps only once or twice in a week at most.

I'm interested in knowing more about your honing methods for your VG steel knives.

Thanks again...

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Since I started using Japanese knives, I've all but retired my old honing steel. I don't like to use it with Japanese blades since I put a very refined edge on my knives. I've noted that with Japanese knives unless using a polished smooth steel hardened to at least RC65-66, the honing steel is counter productive. A honing steel should "realign" the edge only. Amongst the Japanese knife aficionados, Hand American smooth steels are well regarded. Most of the folks who use a honing steel on their Japanese blades seem to prefer them over any other. If you prefer a honing steel, check out the HA steel.

As for my personal practices, I've developed them over a few years. I sharpen my knives with waterstones. I primarily use Shapton Pro stones, although I've tried quite a few different stones. As for my "honing" practices, I originally started with a Hand American leather honing pad which I used with 0.5 micron chromium oxide compound to polish and align my edges. I've since expanded that to include "MDF Hones" which I cut to size from a larger sheet of 3/4" MDF and use with the HA base as a substrate. I use diamond pastes with the MDF hones. I find they do an excellent job, particularly when used with the diamond honing compounds, allowing me to attain a very refined, highly polished edge.

If you're interested in either the Hand American leather hones or their smooth steel, check out japaneseknifesharpening.com It's a site run by Dave Martell, a professional knife sharpener, guru for all things related to knife sharpening, occasional eG visitor, and all around great guy. Dave also does mail order sharpening for Japanese blades. You might also pay a visit to foodieforums.com and knifeforums.com (look for the "In the Kitchen" forum) for a lot of good info on Japanese knives, sharpening, and maintenance.

[WiscoNole]

I use a Hand American "glass smooth" steel. I got it from Dave at JapaneseKnifeSharpening.com. He's a pleasure to deal with and the steel works beautifully. 3 or 4 very light passes provide noticeable increase in performance.

Edited February 3, 2008 by WiscoNole (log)

[yeti]

After reading so much about Japanese knives, this is where I ended up. Shun Ken Onion 10 inch.

Reading all your opinions, and the feel of this knife in my hand really made my choice fairly simple, well just going by what I need, not what I want. Want is a whole different animal! Of course I am afraid it is an animal that NEEDS to be fed, and often!