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Introduction:

Japanese knives, as well as sharpening in general, have become a passion for me. I don't claim omnipotent knowledge of the subject, but I do feel I know enough to share what I have learned from many hours of sharpening this particular style of kitchen knife. Hopefully this small instructional post will help you find the true sharpness of your favorite Japanese knife.

Background Information:

While it is true that Japanese blades are made to be harder than "traditional western cutlery" I do not find them difficult to sharpen, especially the single bevel/concave(hollow ground) backed traditional blades. The inherent design of these knives makes them very user friendly, i.e. they have an angle finder on the back side, you simply lay them flat on the stone and they are at the perfect angle. As with all single bevel/chisel ground blades you never want to raise the back of the knife off the stone, except in one particular case which I will divulge later.

Stone Prep:

Before we get started we need to make sure our abrasive we are going to use is perfectly flat, this is particularly important when sharpening single bevel blades, due to the geometry of the edge you are trying to create. Sloppy, uneven backs on your knives and or out of flat stones will make you weep in frustration when sharpening these, so it's best to get it right the first time.

STONE LAPPING

1. Any very flat substrate can be used for lapping, I have a Shapton Compact lapping plate and Shapton Medium powder pictured, thought the technique will work with any lapping system.

2. Draw large X on the stone you are about to lap, this will help you see when you are flat.

3. Add a small amount of water to the plate, making sure the valleys are about ½ full then evenly add about a teaspoon of powder to the plate.

4. Work the stone back and forth in an X pattern. Try to impart zero bias to the stone. Check the X you made on the stone often, once it's gone you are done.
Lapping The Back:

Almost as important as making sure all of your stones are flat is making sure the back of the knife is flat. Sometimes they come from the maker slightly out of wack and not perfectly flat, this will cause some areas of the edge to hold on to a burr no matter what you do to the back. Thankfully, once this procedure is done it won't have to performed again. I have seen several knives on the forum of late where the back is ground so badly that the two ridge lines on the top and the bottom of the hollow grind are starting to meet, this is not ideal and should be avoided. Please review the pictures.


Procedure:

1. Paint the top and bottom ride lines on the back of the knife with black marker, this will tell you exactly where the back is not flat.

2. Make a few strokes, using the finger position in the picture, on a medium stone, I am using a Shapton Pro 2k. Rub the entire back then check to see where the marker is removed.

3. As the pictures show, the maker is removed right up to the edge, this is what you want to see. The marker need not be completely removed completely from the top ride line, if the edge is being reached, you are good to go.

4. If the marker is not being removed in a certain area, continue abrading the entire back evenly until all of the untouched areas are ground. Don't grind the whole back away for a small area, it will eventually fall into line with repeated sharpening.

5. Continue polishing away with progressively finer grits until you reach your finest stone etc. The knife will only be as sharp as the polish on the back, so the higher the better here. I use my preferred polish stone, the Naniwa 10k.



Bevel Side Techniques:

Once the back of the knife is flat and polished, the rest of the process goes very quickly. You will only be spending minutes on each stone to get the desired result. Of course, practice makes close to perfect when it comes to sharpening.

***Any burrs formed on the front/bevel side need to be removed with the highest grit stone you finished the back with above.***

Procedure:

1. Choose angle based on what knife will be expected to do. My freehand edges always tend to be convex in profile so exact angle definition is not in-play here.

2. Start with a 1k, or similar, and go slow at first to establish the initial shape to your bevel. Once the initial shape is established, the knife and your hand will naturally want to hug that shape, making sharpening easier.

3. Continue abrading the front side until a burr is formed on the back side. Remove the burr with your polish stone using same technique as above.

4. Progress thorough each grit,( I used a 1k, 2k, 5k, 10k), repeating step 3 until you have used your finest stone on the front and back bevel. STOP, check for residual burrs. See pics.


Burr Removal

This is what to do when the edge just doesn't seem right after all of the above steps. I use an indoor floodlight to confirm/deny the presence of residual burrs. To date, it is the best method I have found for this purpose.


Procedure:

1. Confirm burr. Edge will feel rough, and won't cut thin magazine paper cleanly.

2. Make one very light stroke, using your polish stone, on the front/bevel side from heel to tip in a slightly elevated angle than original angle. If the angle is too high, the edge will dig in instead of glide smoothly.

3. Make one, again very, very light, stroke on the back side in a stropping motion, at a slightly raised angle. To high and you destroy the edge, so it is best to cheat down and use the lightest pressure you can muster and still maintain an even stroke. Trial and error is the key on this one.

4. Repeat until edge exhibits ZERO glints etc under that light.

5. Test the edge and admire your hard work!!!!!