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Making a shoji - Part 1

I’ve uploaded part 1 of the making a shoji video. This part covers marking the stiles and vertical tsukeko and kumiko. I hope you find it interesting.


Exercises Part 2 uploaded

I’ve uploaded part 2 of the shoji exercises video.

Next it’s on to making a real shoji, so stay tuned.

New YouTube video - Exercises Pt 1

I uploaded a video to YouTube today that runs through some kumiko sawing exercises in preparation for making a shoji. I hope you find it interesting and of value.


A couple of YouTube videos

I uploaded a couple of videos to YouTube on shaping the rocking chair headrest using a sori-ganna (compass plane) and a small hira-ganna. I hope you find them interesting.


Kindle book published

It’s now on Amazon at the Kindle Store, and no that’s not me on the cover.


The whole process was a lot less painful than I thought it would be. The reference book I mentioned in the last blog entry (The eBook Design and Development Guide) was a great help in learning how to write up effective and efficient HTML and CSS code, although the final few files that I had to make up to properly compile the final book for submission to Amazon caused more than a few headaches. Eventually I managed to fluke the right parts, and it cleared the Amazon formatting checks. So it’s up on Amazon for sale: for only US$4.99.

The Kindle book is essentially the first part of my book
Shoji and Kumiko Design: Book 1 The Basics, although because of the different format—electronic as opposed to hard copy—I had to touch up all the diagrams and photos. I also made a few minor adjustments where I thought they were necessary.

The Amazon site has a “Click to Look Inside” function, so the sample pages and table of contents will give you an idea of what the book contains. In short, the book covers just about everything you need to know about setting up and maintaining a
kanna, the problems that can occur, and how to avoid them.

So for the price of not too much more than a good cup of cappuccino, you’ll have all the information you need to get those thin and wispy shavings floating out from your


Back bevel and ito-ura

A very good question about back bevels was raised in the comments section of the previous blog entry on the ito-ura. I tried answering it in the comments section, but my reply was probably too long for the commenting system to handle, so I’ll answer it here.

The question was: “
I understand why a back bevel isn’t a good thing with a chisel, but why is a very slight back bevel not ok with a plane blade?

The back bevel is convenient on a normal Western plane blade because without the hollow (urasuki) of the Japanese blade, there's a fair bit of real estate on the back of the blade to keep flat. Back bevelling (David Charlesworth's "ruler trick" is possibly the classic example) reduces this to a fraction of a millimetre at the cutting edge. I use this for my block plane blade, and also on the blades in my Stanley planes, which unfortunately are feeling fairly neglected as I haven't used them for a few years.

A properly formed
ura with the ito-ura, doesn't have this large area to keep flat. It's only the thin flat (uraba) at the cutting edge and the two thin flat areas (ashi) to the sides of the uraba that have to be kept flat. Provided the blade has the ito-ura, essentially all the advantages and benefits of the Western blade back bevel for sharpening are already inherent in the structure of the laminated Japanese blade.

So as long as you don't allow the 
atama to sag when polishing the back to remove the burr, it's really quite simple to keep the very thin ito-ura area flat, and a back bevel would simply be an additional unnecessary step.

The second, and probably less significant, reason is that on the final finishing plane (
jō-shikō kanna) the chip-breaker should be set back 0.1–0.2 mm, and about 0.2 mm on the intermediate finishing plane (chū-shikō kanna), which is very close (in Japan, this is referred to as "kami no ke ippon" — the width of a hair). A back bevel has the risk of interfering with the contact between the uraba and the chip-breaker.

Forming a back bevel to increase the cutting angle for planing difficult hardwood is a different matter. I still wouldn't give the Japanese blade a back bevel though. For hardwood with difficult grain I'd either use a
kanna dai with a higher cutting angle, give one of my Stanley blades a back bevel, or use a bevel up plane with the blade sharpened to a higher cutting angle (I have the Veritas low-angle jack plane for this).


Ito-ura and problems

The blade ura is one area that highlights where there may be problems with either the sharpening technique, or the ura-dashi and ura-oshi technique. I cover this in some detail in the book, and I thought I would include this section from the book here, because the ura and trying to maintain it in its optimum shape certainly is one aspect that can cause a degree of frustration and exasperation.

This is directly from the book. It is, of course, not the book layout. The copyright marks on the images are purely for the internet. They are not in the book.

Shokunin in Japan are very particular about how the blade ura looks. It can be a source of pride, or it can cause shame and embarrassment. A properly shaped ura not only makes the blade and the kanna more efficient, but is also a testament to the shokunin’s skill and his respect for his tools. A badly shaped ura shows a lack of care that is more than likely to be carried through to the shokunins work.

In this section, I’ll describe in detail how to create and maintain an
ura you can be proud of, and how to avoid the bad habits that will prevent you from achieving this.

The type of
ura to aim at is an ito-ura.

01 P27

Ito is the Japanese word for thread, and in an ito-ura the uraba is as thin as a thread, or in reality about 1–2 mm. The hard steel and soft iron lamination structure of a kanna blade is different from that of a chisel, so they have different ura, as shown in Photograph 28. The chisel ura is broader, and is known as beta-ura. A reasonable beta-ura is normal on a chisel, but not on a kanna blade. This is the type of ura you should avoid.

02 P28

There are a number of faults that can create a badly formed
ura, but the advantage is that they all affect the ura in a different way so if you are having difficulties in obtaining or keeping a good ito-ura, the ura itself will tell you where the problem is.

The main faults are: a failure to tap out adequately, and closely linked to this, honing the back too much, especially on the coarser grits; an uneven distribution of strikes when tapping out; honing along a single line; honing at an angle not perpendicular to the stone; and, perhaps the most common, allowing the blade
atama to sag while honing.

Failure to tap out adequately
This can be a common problem when tapping out from the uragire condition, but it can also occur if you don't properly tap out a new blade that has a slight elevation at a point along the cutting edge. This aspect was covered in the Adjusting a new plane section beginning on Page 25.

The following diagram shows what happens when the tapping out is inadequate. This can often be caused by a degree of tentativeness when tapping out, especially in the early stages. Although not as bad a problem as not tapping out at all (see Page 39), over time the problem will continue to worsen.

03 D41

The way to solve this is very simple indeed. If, after tapping out, you hone the ura on the coarse stone and the scratch patterns reach both sides of the blade but the uraba has not widened sufficiently or not at all, STOP. Don't try to force out the uraba on the stone.

If you continue honing until a reasonable
uraba appears, you will hone too much, and while you may end up with a thin uraba, the ashi on both sides will be too thick. Once this happens you are virtually stuck with fat ashi for the rest of the life of the blade.

This is also the case if you don't tap out adequately on a new blade. If you’ve tapped out adequately but hone too much on the coarser stone, you will end up with a

Tapping out must be a careful and deliberate procedure, but that does not mean you should be tentative. Tap, check, tap, check, and continue until a sufficient bulge appears, regardless of how long it takes.

Uneven tap distribution
In this case, tapping has been concentrated too much in one area so the bulge in the urasuki isn’t uniform. The following diagrams show what happens when the tapping is not even.

(1) Tapping too much or too strongly in the center and not enough on the sides: This can be a tendency in the early stages, where the center seems the safest.

04 D42

(2) Tapping too much or too strongly to one side: This quite often happens if the uragire is more to one side, and you fail to account for it .

05 D43

If you find that your uraba is beginning to look like this as you hone, in either of these cases, simply stop and tap out some more in those areas that are too shallow. An uraba that’s too wide can be fixed after a few sharpening sessions, but once one or both ashi become overly wide, that’s the way they’ll remain.

Honing along a single line
If you hone the ura along a single line on the sharpening stones you will create a ridge, which is another sign of poor technique. Therefore as you hone the blade along the stone, especially the coarser grit stones after tapping out, gradually move it backward and forward 10–20 mm to prevent the ridge from forming.

06 D44

Honing at an angle
When honing the ura, the blade should be perpendicular to the length of the stone. If the blade is at an angle you run the risk of an ura that looks like the following.

07 D45

Sagging atama while honing
This is perhaps the most commonly seen fault. Kanna blades are quite large and heavy, and there is a tendency to let the atama sag while honing the back, giving the ura somewhat of an hourglass shape. The following diagrams show this.

08 D46
09 D47

When honing the back, you should have a feeling that you’re lifting the
atama up slightly with your supporting hand as you apply pressure to the bevel with your other hand.

10 D48

You shouldn’t actually raise the
atama as this would give you an unwanted back-bevel, just feel as though you are. That way you are giving the blade proper and even support, and you’ll avoid the hourglass shape. Unfortunately, once you have the hourglass ura, you’re stuck with it until you’re able to sharpen past it, which could take several years.

I mention earlier in the book that a properly formed ura is not just a matter of aesthetics. There is a very sound reason for the ito-ura and avoiding ashi that are too wide. Hopefully the above can go some way to help you achieve that.


Kanna maintenance

It’s a bit quiet at the moment, so an ideal chance to do some serious maintenance on my kanna. All the dai need a bit of work, and a couple of the 70 mm blades need to be tapped out.

This is what happens to the
tsutsumi as the sole of the kanna is conditioned numerous times.


tsutsumi is a small extension from the bed, and serves no real purpose. It does, though, indicate quality in that the dai has been made by hand and not by machine. Over time, these remains of the tsutsumi will gradually disappear with each round of sole conditioning.

This is one of the blades that needs tapping out. This is the blade I tapped out in my blog entry
here at the end of April, and this will be the second time I’ve tapped it out since then. My other 70 mm plane blades have also been tapped out a few times since then as well. I sharpen my blades often, so tapping out is a regular occurrence.


I had to work on this blade a bit, so you’ll notice that the flat is very thin, and in one place, virtually gone altogether. When the flat disappears, this is called

Ura-dashi (tapping out)

Finished the latest project …

And having a few days of relaxation to spoil daughter, who’s going to spend a few days with us from Tokyo, before I get started on the next major challenge.

A few people from one of the forums mentioned the
ura-dashi process after reading my piece on tuning my plane, so I thought this would be a good opportunity to describe how I carry out this important step in the correct use and maintenance of Japanese planes.

The overall process consists of two parts:
ura-dashi (裏出し) tapping out; and ura-oshi (裏押し) flattening the back.

Ura-dashi is normally done when the blade edge has been sharpened to the rim of the hollow (called the ura-suki 裏透き). It can also be done on new blades where the ura is not flat, either on one side or the other, or in the middle.

I’ll emphasize here that there are many ways of tackling this, and provided they work, each one is as good as any other. This is the method I use, and it works for me.

The first thing to do is check the cutting edge in the mouth. Eventually with sharpening over time the cutting edge will extend beyond the sides of the mouth (
ha-guchi), and if this is the case you will need to file back or grind the mimi (blue arrows). You will know if this needs to be done because the shavings will become caught up in the mouth.

This plane is OK (green arrows), so on to the

This photo shows where to hit with the hammer.

Too close to the edge will crack or chip the hard steel (
hagane). I only tap on the back half of the blade bevel (kireba 切れ刃). In the case of this blade, the left-hand side of the ura-suki (hollow) is slightly deeper, so I needed to tap slightly more on this side. The key point here is to look closely at the blade, and find out what its characteristics are, if any.

I use the edge of my workbench to support the blade, as shown in this photo.

My workbench is Queensland maple, a reasonably firm hardwood. You can use any firm surface provided it gives good and solid support for the blade. I’ve rounded off the edge of the workbench for the blade, and filed the vertical corner to give a flat reference surface for my left forefinger. In Japan I used the end grain of a large board of
keyaki (zelkova). Anvils, and short cut-offs of railway track are also used.

I use the corner of my
gennou to tap out. This one is about 200 g, and it gives me good control. Any size or weight is OK provided you have control over where it strikes.

The point here is not to hit too hard. Many moderate taps is better than a few hefty smashes, which will almost guarantee a crack or chip. It also ensures better control of the hammer. You can tap slightly harder further away from the cutting edge, but the closer you get to the
hagane, the gentler the tapping should be. And always ensure the blade is fully supported at the striking point, so move the blade rather than the hammer. That is, always strike at the same point, but use your thumb to move the blade to the left, right, up and down.

The next photo shows the result - an even distribution of tap indentations. And importantly, no chips or cracks. As I mentioned before, from this I continued to tap out with somewhat more bias towards the left-hand side because of the blade characteristics.

That completes the
ura-dashi, now on to the ura-oshi.

I use my normal Shapton stones for ura-oshi. It is important to make sure that the head of the blade (atama) does not sag down as you flatten the back. So when doing this, you should feel as though you are lifting the head up slightly while applying the downward pressure to the edge, as shown in this photo.

You shouldn’t actually lift the head up though, as this would give the blade an unwanted back-bevel, just feel as though you are. Regularly check the shape and adjust the pressure as necessary.

This is the blade from my first plane I bought quite a few years ago, and this is what happens if you let the head sag. This was a source of great embarrassment for me at the College, and complete humiliation when my instructor looked at it and simply said “Hmmmmm”.

First, I give the back a few swipes on the 5,000 grit stone to check the condition of the ura-dashi, and make sure there’s an even protrusion. If that’s OK, I move to the 1,000 grit stone.

Another point to take care with is that as you move the blade left/right on the stone while flattening the back, you should also move it forward and back 10-20 mm so that a ridge doesn’t form near the cutting edge.

Then progressively through the 2,000 grit…

5,000 grit…

and 8,000 grit.


This is how it ends up. A clean even ito-ura.

The geometry of the blade has been changed slightly, so I also have to check how the blade sits with the chipbreaker, and adjust the chipbreaker as necessary.

From here it’s on to the normal sharpening process.

Tuning my finishing plane

The weather has been a bit all over the place over the past few days, and while I was waiting for the finish on a couple of frames to dry, I checked my finishing plane for movement. The changing weather had affected it, and it needed to be tuned. It wasn’t too bad, and normally just a couple of minutes with the dai-naoshi kanna would have fixed it, but thought I would completely tune it from scratch, and put the photos here to show how I do it.

This is my finishing plane for rails, stiles and narrower pieces, so I have three touch points, shown in the next photo: what we would perhaps naturally call the front of the plane but is actually the back (
daijiri 台尻) - 1; the area forward of the mouth - 2; and the front (daigashira 台頭) - 3. The surface between these three points is slightly concave so it doesn’t touch the wood being planed. The plane therefore “glides” along the planed surface on these three points. Because this is my finishing plane, these concave areas between the touch points are relieved only very slightly.


This photo shows what I use for tuning.
tuning tools
Yes, it is sandpaper, and it works well. 220 grit sandpaper stuck on to 16 mm MDF, the plane being tuned, my dai-naoshi kanna (a scraper plane), and a small gennou for removing the blade. I also use a chisel.
First, I retract the blade slightly so it’s protected from the sandpaper, but down far enough so that it still applies the normal tension to the
dai. Then I completely flatten the sole (dai shitaba 台下端) on the sandpaper using a normal planing motion.

If you’re concerned about grit from the sandpaper attaching to the plane (it didn’t seem to worry any of the master craftsmen instructors at the College), you can wipe the sole with turpentine or the like after using the sandpaper.
Once the sole is perfectly flat, I then start on the concave areas between the touch points.
First, the parts to the left and right of the mouth. I simply use a chisel to carefully pare away a small amount of wood shown by the red arrows.

I now work on the concave area between touch points 1 and 2. To start, I simply turn the plane around so it’s perpendicular to the sandpaper, and carefully sand the required area. Care must be taken not to sand too far either to the left or to the mouth.

I then use the dai-naoshi kanna to cleanup and refine this concave area. As an aside, I always sharpen the dai-naoshi kanna blade before I use it. The sharper the blade, the better, cleaner and faster it removes fine scrapings of wood.

Next, I work on the concave area between the mouth and touch-point 3 (daigashira) with the dai-naoshi kanna.

I also use a sharp chisel to scrape away wood from near the mouth. This gives more control close to the mouth, and prevents the possibility of accidentally scraping away parts of touch-point 2.

Once I’ve finished this, I check the sole lengthwise, across and diagonally. The area in front of the mouth is especially important.

After I’ve finished the
dai, I check the blade. I sharpen often during use, so I have to tap out (ura-dashi) quite regularly.
Here, the flat (ito-ura) is becoming quite narrow, so I’ll need to tap-out at the next sharpening session.
This is my finishing plane, so I progress through the grits up to 12,000. I use Shapton stones - 1,000; 2,000; 5,000; 8,000; and 12,000. For my non-finishing planes, I stop at the 8,000 stone. After sharpening I put the blade back in the plane and give it a try to make sure the tuning was successful.

And as they say…

The proof of the pudding is in the eating.

Landscape 2 - Finished!

Finished the piece on Friday. I finished the actual kumiko work on Wednesday, then a couple of days to fit the frame and backing, and put a few coats of finish on the frame. So after a few anxious moments about the cut-off date, I eventually had a week to spare. It’s now safely tucked away. The photo below is the final section. A multi-coloured collection of kawari-asa-no-ha.

Final section of landscape

So today, I set about on some long-overdue maintenance on the machinery, then upstairs to give the hand tools a bit of TLC.
First of all, the
ha-ganna. Eventually, I’ll add a section to the website describing some of the specialist tools I use for the kumiko, but these four planes are the most critical for the fine detailed work. Without these planes, it would be impossible to cut the short pieces, which can be less than 2 or 3 mm in length.

They work by cutting angles across the grain. This is fine with the soft timbers, but the harder timbers, especially the bloodwood, purpleheart and saffronheart I used in this piece certainly took their toll. My kumiko were 1.6 mm wide, so even for the pieces that ended in a “v” shape, such as the ends going into the vertices in the
kawari-asa and yae-zakura in the photo above, the planes had to cut through 0.8 mm of very hard and dense wood. And for the pieces that had to be cut all the way through, such as the shorter pieces on the kawari-yae-zakura and yae-zakura, it had to cut down to the full 1.6 mm. The photo below is the end result of using the hard timbers. Painful, but one of those unfortunate things that can’t be helped.
All the ha-ganna have some form of blade damage as above, but a few hours on the stones and they’ll be back as good as new. Then a couple of days off before I start on the next project.