how the Japanese use waterstones for sharpening

Did you ever see a better sharpening set up than this?

The water trough has running water fed from a stream so is continually flushing away the swarf and slurry from the stones. This sharpening trough was set up on the edge of our tea house worksite in Japan and the Japanese carpenters would visit regularly to keep a perfect edge on their tools. I have been sharpening with waterstones in the UK for many years but I learned a lot from watching and working at this sharpening trough.

Most folk in the UK soak the stone and then just splash a little extra water on the surface, the running water below the stones allows the Japanese to continually sloosh water over the stones keeping the surface very open. The other big differences were the different brands of stones which cut much faster and they continually cut back the surface of the stone with a big diamond dressing plate thus exposing fresh abrasive and flattening the surface. This means the stones are very much seen as something that has a limited lifespan, like an abrasive belt on a grinder but as the stones wear thin and break they become useful as slip stones, these too are flattened  regularly on the diamond plate, here is Tak honing his chouna blade with a small piece of waterstone, note the wooden bucket of water to keep the stone slooshed.

other differences are they have lots of stones and choose whichever ones are appropriate for the job, coarse ones for renovating chipped of damaged edges and lots of medium to fine ones for honing then extra fine stones for finishing. Most finishing stones were natural whilst most coarse and medium stones were man made. The skill level of the Japanese carpenters was impressive, they have all put in many hundreds if not thousands of hours sharpening with waterstones and so it is completely second nature, their hands just do the job without any thought, here is Tani. I was surprised how much pressure they use too, the trough is very secure and they press down hard and cut very fast. Sharpening a plane blade on three grits of stone would take maybe 4 minutes.

And here is hewing master Amemiyasan, whilst sharpening his axe his phone went off so he answered it and carried on sharpening without interruption. He is using a small piece of broken waterstone which has been glued on to a piece of wood, this is what they tend to use for axes. Often they will glue thin and fragile waterstones to a wooden board too allowing them to use the whole stone down to the last mm.

Nicola made this is a short video whilst in Japan showing finishing a plane blade on a natural waterstone, note how the edge is washed and then he feels to check all the bur is removed. Through practice they are tremendously sensitive to this and can feel tiny burs that I need strong magnification to detect. Also note the stone is washed and put away, the Japanese are very tidy and they want that stone to be ready to use next time.
[vimeo http://www.vimeo.com/13975599 w=400&h=225]
Japanese tool sharpening from Nicola Wood on Vimeo.

At the Kesurokai event in Germany 2005 the Japanese carpenters did all their sharpening squatting on the ground like this. This position allows a lot of pressure to be applied, no water trough here but they kept a bucket handy to sloosh the stones and a gardeners spray bottle to keep the surface flowing.

Hannes my German friend spent 2 years as an apprentice to a master temple carpenter in Japan and when he came over and helped me build my new timber framed woodshed he also gave us lessons in sharpening with waterstones. Hannes ran sharpening courses with our friend Michail Schutte in Germany last year and I think they plan to do it again. If there was interest I could ask him to come and run a masterclass in the UK in 2011.

And now back to my own sharpening and how it has developed since Japan. Before Japan I used DMT diamond stones (fine and extra fine) or power grinders (a tormek and a big belt linisher) for rough grinding and then waterstones only for the finer work from 6000 grit downwards. I now realise this is because the common stones in the UK are not so good at the coarse end. I have king brand 1000 grit stones but have never really got on with them, they are very soft and wear quickly so need continual dressing but despite that they do not cut very fast. I now have some Shapton stones, a 1000, 1500 and 5000 which cut at around twice the speed yet do not wear as fast, they cost twice as much but for me they are worth it because it makes the difference between a stone I use and one I don’t. I also bought in Japan a big diamond flattening plate to dress the stones, I did this before with my DMT diamond stones but this plate is bigger so trues the whole surface better and is coarser so cuts faster. Here are some of my current stones.

From the top left natural stone about 12000, shapton 1500, shapton 5000, shapton 1000, shapton glass stone 16000 (yes really 16,000) spyderco fine stone, spyderco extra fine.
Bottom row, DMT extra fine, Japanese diamond stone dresser, unknown stone very like a shapton 1000, natural stone c12000, king 1000, king 4000, king 6000.

Of these stones the shaptons are far superior to the rest, the king 1000 is barely worth having, I would just as soon use emery paper stuck to a woodblock, the king 4k and 6k are reasonable stones, in fact the 6k makes a decent finish stone at not too high a price I always finished with autosol metal polish on a board after this stone. Now I follow it with the 12k natural and 16k shapton instead. The spyderco stones are OK as fine finishing stones but they do not remove metal fast and have very little feel or feedback, the knife tends to skate on the surface as if on glass where even the 16k shapton feels like it is grabbing at the metal and cutting, this allows you to feel the bevel you are trying to sharpen much better.

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11 Responses to how the Japanese use waterstones for sharpening

  1. Jonas September 12, 2010 at 11:04 am #

    In the last picture I see that in England you soak your waterstones in beer.

  2. Le Loup September 12, 2010 at 11:49 am #

    Good post, good to know I have been doing it right all these years. I thought everyone did it that way. Always more to learn.Regards.

  3. julesheath September 12, 2010 at 12:32 pm #

    Thanks for another interesting post Robin. What would you suggest as a good starting point for hobbyist woodworkers?

  4. Jock September 13, 2010 at 3:35 am #

    "Jonas said… In the last picture I see that in England you soak your waterstones in beer." Must be where the term "half cut" came from eh

  5. Robin Wood September 13, 2010 at 8:41 pm #

    @Jonas, the beer at that stage was just for Hannas. I have one rule about knives and alcohol, I never open even a beer until the knives are put away.@Julesheath I advise folk on courses to start with a mixed pack of wet and dry emery paper from B&Q or Halfords, stick it to pieces of wood and this gives you a range of grits from say 120-1000 so coarse to fine. 1000 is still not fine enough for a good edge so the cheap option is autosol metal polish (halfords), some use it on a leather strop (old charity shop belt) fixed to a board, I use it direct on a piece of planed softwood or MDF. The next step up from this is 6000 grit king waterstone which comes after the 1000 grit emery and before the autosol. As with most woodworking technique is more important than what you use though.

  6. Steve Branam September 14, 2010 at 12:06 am #

    For all our obsessing about sharpening, I love the nonchalance as they just do it, no fussing around!

  7. Robin Wood September 14, 2010 at 6:34 am #

    Me too Steve but isn't that just a question of where we are at on the learning curve. We all go through phases of learning, experimenting, trying out, practicing, doing, questioning, experimenting more, doing more until we get to the stage where we have done it for so many hours that it becomes totally internalised. We all do difficult manual tasks nonchalantly, driving a car is incredibly complex, typing at a keyboard. We just forgot how much time we took to get to that stage.

  8. JRC September 16, 2010 at 3:42 am #

    All very, very interesting. But, as I have said before elsewhere, Japanese tools are tempered like Goldilock's porridge, just at the right temperature, so the waterstones cut them. Beautiful system. Nowadays I think western tools are tempered too hard. So waterstones won't cut them at all. An extreme example: try waterstoning a (good quality) chef's knife on a waterstone. A Sabatier, say, or a Wuesthof. I, at least, can't do it! Emery paper will cut them, or a belt sander, or of course diamond. Manufacturers do this on purpose, so that the edge will last, because they know quite well that the users can't or won't learn to sharpen them. Thus, I buy japanese tools if I can, because I can sharpen them on my waterstones. Lee Valley, at least, will give you the Rockwell hardness (Rc) for most of the tools they sell, so with a bit of practice you can tell if it's waterstoneable or not.

  9. Steve Branam September 17, 2010 at 10:47 am #

    And right there you have a nugget of real wisdom, Robin! It's such a deceptively simple task (how hard can it be to rub a piece of metal on a stone?), that at a conscious level we fail to recognize that complexity.Yet at an unconscious level, we do recognize it, imbuing it with such mysticism that we invent all kinds of jigs and stones and grinding techniques.You said the magic word, practice. Whether sharpening, or cutting to a line, or making a complex joint, we need to practice it until we can do it without thought, like walking.I will incorporate that wisdom!

  10. Shannon September 17, 2010 at 3:51 pm #

    Great post Robin. I love your point in the comments about practice. Many of my teachers over the years (woodworking and not) endorse the method of learn it then forget everything and just do it. I am curious about your Japanese flattening plate. You mention it cuts really fast because it is coarser. How coarse in comparison to the more commonly available DMT stones? I have an extra coarse DMT that I have used for rough work, but I'm almost afraod to take it to my fine shaptons for fear it will put deep scratches in them.

  11. etorix November 5, 2010 at 2:22 pm #

    the vimeo video plays soundtrack-only for me, no picturenice chopping noises thoany chance of utube-ing it?

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