Care for Japanese chef's knife - chips, rust, etc

Clove oil and camelia oil aren't the same. Camelia oil as sold for cutting tools is actually a blend of camelia oil and the bulk is mineral oil. The scent is very light and pure camelia is used in some places as cooking oil.
 
Also, if your knife has two shiny lines on the back, one at the edge and one running along the spine, don't grind so hard as to widen these lines. You will warp the edge. Treat the back of these knives like a hollow ground straight razor or a chisel's back. A quick swipe or two on this side is all that is needed. In some cases, the back is not totally flat and must be ground slightly, use a magic marker and paint the edges, when it is all gone, you are flat.
 
Just to illustrate further what Yuzuha already said: These are my heaviest users. The Usuaba (square blade) had a blade profile that was just a tad to extreme for my purposes (around 18 deg included). The Usuba is designed as a pure vegetable cutter using a slicing motion. I like the bladeshape but use it occasionally more as a general chefs knife which the edge did not support. So I increased the bevel angle a little...mayby 25 deg included now. I raise the edge further on the finish stone as you can see. It is wrought iron and Shirogami (white paper steel). The rust flecks are all from onions.

The other is my main kitchen knife, a Deba with a massive blade. It is designed to rough cut fish. The heavy style is designed to cut through fish bones and the thick blade is used to open up the cut, which works obviously only in flexible material such as meat or fish. It doesn't work very well with carots for example. Since it is single bevel, the include angle is still pretty small, 30 deg maybe. The geometry is pretty pronounced on this one. The bevel is pretty strongly convex (even though I have flattened it out somewhat, as you can see) and non-bevel side is pretty deeply dished. At first glance it looks actually flat but once you look at reflections in the blade you can see how the reflection curves. I know very little about this knife, other than that I like it very much. Is a stainless steel laminate. Hey, Yuzuha, any chance you can make out the characters on the blade and know what they are saying? I have tried before but had no luck.

The problem with the common advise to "lay the bevel flat on the stone" is that most japanese kitchen knives have bevels that are actually convex. So there is really no way of laying them completely flat on the stone. You have to pay attention to the edge and have to make sure that the edge makes contact. Mark the edge with a blackmarker and see if the marker is being abraded.

If your edge is from a highly hardened steel like shirogami or aogami, you really need a waterstone. Common oil stones and ceramic stones (or diamond stones for that matter) are to hard and and will chip and fracture the edge.




 
Hello all. First time poster long time lurker here, great forum!
Could the chips result from poor storage? You don't say, but if a fine ground knife like this is dropped into a drawer I guess it could chip?
 
HoB said:
Hey, Yuzuha, any chance you can make out the characters on the blade and know what they are saying? I have tried before but had no luck.

The problem with the common advise to "lay the bevel flat on the stone" is that most japanese kitchen knives have bevels that are actually convex. So there is really no way of laying them completely flat on the stone. You have to pay attention to the edge and have to make sure that the edge makes contact. Mark the edge with a blackmarker and see if the marker is being abraded.
Click to expand...

It isn't in machine readable format so I can't use any of my favorite look-ups... I could probably translate it but it would take an awful long time hunting through my kanji dictionary. I'll ask around and see if I can find someone who can read it for me.

Ah, the clam-shell edge... some gyuto have them... sort of a slight convex on the back side and larger convex on the front side so the bevel profile resembles a clam viewed from the side. Supposed to make for a durable edge. Saw some videos on how to do those... involves lifting the spine up slightly at the end of a stroke on the stones, but it is a knack that would take practice.

Oh, here is a video of using a nakato (medium stone) http://www.suisin.co.jp/Japanese/tokusyu/move-imag/inox-honhatsuke01.wmv and here is one using a shiageto (fine/polish stone) http://www.suisin.co.jp/Japanese/tokusyu/move-imag/inox-honhatsuke02.wmv (not sure but it looks like he's using a Naniwa 3000 grit stone since it is pink and has a plastic base) This one shows clearly that the back should be laid flat on the stone and only for a few strokes compared to the front. It also shows how to handle a stubborn burr by making a few gentle strokes on the front side at a high angle (weakens the burr and bends it to the back) and then laying the back flat on the stone for a few more strokes.
 
I don't recognize the characters either. I could tell you what it's not, but not what it is. You usually don't see "made in Japan" stamped on them either, but I have seen some new knives from Japan stamped in this manner, I think there is some new import rule B.S. that requires it. How old is the deba?
 
Welcome, Jim!

Very cool links Yuzuha! This guy clearly has done that before! I love how he lets the fingers glide over the blade. Imagine what would happen if he slips off the blade....:eek: .

You can see at the end of the video with the coarse stone, how he trues up the back side. He takes actually quite a few back and fourth strokes, but not nearly as many as for the bevel side. Sorry that I didn't write this clearer, yes, you keep the back always flat on the stone and after trueing it you just pull of the burr on that side. When I said you could lift even the spine of the back side a bit that was only, if you would want to increase the angle a bit. You could do that just by working on the bevel side, or by increasing the angle a tad on both sides. On the Usuba I increased the angle mostly on the bevel side, but I also lifted the back side just a hair. That mitigates the "pulling" to one side due to the concave surface. In the end it is all about what works for you. A japanese cook would probably flinch if he would see what I use my Usuba for....but then again, I haven't had his 12 year apprenticeship either, nor do I own the average 30 different kitchen knives either :eek: :(.

The Deba is either 7 or 8 years old, I can not remember which and is well loved and used as you can see. The Usuba is 6 or 7 years old and is this one:
http://www.epicureanedge.com/shopexd.asp?id=566&photo=1&size=b&websess=82102420028147
I love that it has come down in price even further since I bought it. IMHO it is by far the best bang for the buck in kitchenknives period (I mean the entire series). They are very well made, and come incredibly sharp. The epicurianedge gave the series their highest rating (five stars) for both initial sharpness and edgeholding and four stars for balance (they are obviously very blade heavy), even though they are substantially cheaper than most other blades sold by epicurianedge (great people and shop by the way, is an offspring of bladegallery). You can see in the picture above that it also has "Japan" stamped on the blade. The only drawback with this series is really, that they are not stainless and no matter how careful you are, you can not avoid discoloration. Expecially onions and fruits will blue the steel because of their acidity. The flecks on the back side are individual onion "dices" that stuck to the blade while I was dicing serveral onions. In a longer cooking section I might use a blade for an hour straight and might not have the opportunity to clean of the blade and re-oil it, till I am done. The black stuff on the bevel is and artifact in the image. That spot on the blade is not any darker than the spots on the back side. I took the pictures last night in fading light and they are both a bit underexposed.
 
Wait a second, this guy in the video draws of the burr on the FRONT (bevel) side. That is unusual. You can actually see that he increases the angle quite a bit for that. These videos are so cool!
 
Well I found your deba http://www.hamono.co.jp/page/page564.htm The kanji appears to be 清網作 which is kiyotsuna josaku http://www.knifeoutlet.com/shop/10browse.asp?category=Kiyotsuna+Josaku+Cutlery-jousaku Which you must have gotten at Hidatool http://www.hidatool.com/kitchen/Kiyotsuna.html or http://www.japanwoodworker.com/product.asp?pf_id=12.224.21&dept_id=13167 the 上作 part is josaku ( じょうさく in hiragana) and means "good crop" or masterpiece and can also be written 上策 (exellent plan or best policy)
 
Yuzuha, you are the best! No I didn't buy it from hidatool. This was at the very beginning of my knife appreciation and my parents bought it as a gift for me at a pretty exclusive and expensive general outfitter in Germany, which isn't specialized on knifes or cutting instruments. They do some research but they are no experts by any means.

I will admit I was a bit embarrassed by the poor condition I have shown my knives in...a weak moment :D. Life has been pretty hectic lately and I lived of fast food for several months now and these knives haven't seen the TLC they should have received (expecially the Usuba). So I figured I would dress them up a bit (I made the photos a bit smaller, hopefully it works. The Naniwa really does a nice job of polishing up the hagane :D.



 
Whoa..how do you use wrought iron in cutlery?
BTW: Aren't waterstones even harder/cut faster than ceramics will?
 
The slabs on the side or sides (depending whether it is kasumi or warikomi style) which are called the jigane and are surrounding the hard steel core called hagane are traditionally made from wrought iron. It is soft and tough, ideal to dampen and absorb the shock. The hagane with the actual cutting edge is of course a high carbon steel. Wrought iron has the added advantage that it rusts and especially pits less that most non-stainless steels. A trivia note: Japanese smithies often have an old anchor or anchor chain lying around from which the wrought iron is salvaged.

The abrasive in waterstones cut faster and depending on the abrasive may be harder than oil or ceramic stones, but the bond between the abrasive particles is very soft. The bond is either a resin or a clay or also a sintered ceramic. However the ceramic matrix of a water stone does not compare to a ceramic stone as, lets say, the Spyderco benchstones. Even though it is a ceramic bond, it is very soft and porous. For more on the bond of waterstones, Yuzuha is probably the person to ask.
 
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