So… I discovered about Japanese Knife Company online, and also that they ran knife sharpening classes. Which was kind of handy, as colleagues gave me a set of Kai Seki Magoruku knives about six years ago, and that I’ve not been a pro at keeping them maintained… The shop is in the 12e, so not exactly next door to me, but it was a great excuse for a (lengthy) expedition for a two-hour class that was well worth the time (though it was actually a lot more time than that–many thanks are due to the H who did the snakelet wrangling).
The shop itself is kind of a Mecca for Japanese knife lovers–they sell everything from entry-level (around 100 euros) to, er, much much more expensive. They also sharpen knives: in fact, while I was there several people (mostly professionals, that I could see) dropped their knives off and came in to buy supplies, and they sharpen both Japanese and Western knives. In fact, if I was in the market for a knife sharpener they’d probably be among my first choices.
What follows are my notes, which are kind of fragmentary because I wasn’t actually taking notes, rather trying to follow along 🙂 No guarantees whatsoever, this is what I understood and I’m not a pro (and it’s also knife sharpening 101–you can find a better class of advice here at Serious Eats).
The class started with an intro course on the various kinds of steel: stainless steel is what most Western knives are made of, and is resistant to corrosion, flexible and middling solid–mostly it doesn’t hold an edge well, which means you have to sharpen aggressively and often. Carbon steel is not as flexible but holds an edge better: the drawback is that the more carbon you put in a blade, the more fragile it becomes. Also, it’s more susceptible to corroding, which means that you usually add some other metal like chromium or tungsten so that your blade doesn’t rust at the mere sight of water. Some bright souls came up with the idea of laminated steel, which is sandwiching a hard steel blade (for the edge) between two layers of softer steel: a combination of a good edge, an easy to sharpen blade (because of the soft steel), and something that won’t actually chip *too* often on you. From there on, you climb into more worked steels: Damascus Japanese blades are made with several of these layers (anywhere from 30 up) and are a. more expensive b. more durable.
(then it gets more technical, and I confess I got a little lost, especially as most other participants were enthusiasts about steel–I felt very much like a hobbyist who’d wandered in by error at some points 🙂 Also, it will not surprise you that I was the only woman on that course, which mostly became a problem because the counter was very high and I had to stand on a stool to make sure I got the right height for sharpening)
Sharpening stones have different grits: the lower the grit the coarser the stone. 120 is what you use for a stainless steel, and the more carbon there is your blade the higher you need. There’s generally two (or more) passes necessary: you go from a coarse grit to a finer grit, so for instance the knife we sharpened was stainless steel and we had a 120/1000 stone; a 3000 stone will have close to zero effect on a blade that’s low on carbon, but a 6000/8000 stone might well be all you need to keep a Damascus knife sharp .The coarser the stone, the more metal it shaves off from your blade, which of course is bad for the longevity of high-carbon blades. The whetstones are waterstones, which means you have to moisten them with water (how depends on manufacturer’s instructions, the ones we had had to be completely immersed), and then keep wetting them to make sure your knife doesn’t bite into them (the coarser your stone, the more often you have to sprinkle water on top of it). You also have to semi-hemi regularly flatten them (he did this with a diamond stone in the shop, but advised us to use a ceramic tile and lots of water at home as it was cheaper–it won’t work on 120 stones, but anything from 1000 upwards can be maintained flat with this method).
The key to having a sharp knife is having a constant angle along the length of the blade–it’s not always the same angle (some knives are 70°/30° for instance), and it doesn’t necessarily have to be the original angle the knife was given (though if you deviate too much from it you’re basically reshaping a knife, which isn’t recommended). Japanese knives are usually and roughly a 15° bevel, but you can have 16/17/18 as long as you keep that angle. Western knives are more U-shaped: the angle is closer to 22.5°.
We then moved on to practice, basic gestures etc., which is where, uh. I discovered that basically I can’t keep a constant angle when moving a knife over a whetstone. Remember the bit about the angle being key? Yeah. Turns out I’m not very good at it. “abysmal” would be a better description of what I can do, in fact. They finally took pity on me and gave me a guide, which isn’t 100% recommended but–for me–made all the difference between having a disastrous blade and something that was semi-hemi-correct.
End result is also that our knives were in a rather disastrous state due to neglect: the blades were chipped in multiple places and basically I’m going to have to redo them from scratch. It also turns out they’re this kind of weird limbo thing where the steel isn’t very much enriched in carbon, making them closer to a Western knife–but shaped like Japanese knives. Go figure. Anyway, I walked out of there with a coarse stone, the guide (which they were kind enough to leave to me), and instructions on how to get them up to reasonable shape.
I. Hum. Also got a laminated-steel nakiri because it was so pretty. Sorry not sorry.
(and would I recommend the class? Definitely if you want to get the basics on knife sharpening on water stones, and not only for Japanese knives. It’s very hands-on, they’re super nice even to a total novice like me, and I hope I can put some of that into practice… Though you might curse me afterwards, as their knives are so pretty. So so pretty. They have several locations in London as well, though their sharpening classes are an order of magnitude more expensive than what I paid for this one).