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HOME > MAINTENANCE > Sharpening your knife

Sharpening your knife

The difference between a whetstone and a sharpener
 A knife's sharpness has two aspects; the sharpness of the blade edge, as well as serrations invisible to the eye. Speed sharpeners sharpen the blade edge into a V-shape, but serrated teeth are more difficult to sharpen and speed sharpeners eventually diminish the sharpeness. If the blade is sharpened with a whetstone, not only can you sharpen the blade, but also you can form serrations on the blade. Speed sharpeners are particularly unsuitable for the GLOBAL-PRO range, as this range features knives with very sharp blades, and usage of a speed sharpener causes crushing of these sharp blades.
Whetstones
We recommend that your knife be sharpened with a whetstone when its edge becomes dull. Whetstones can be largely divided into three categories.
* Rough grit - grits up to #600 (used for repairing small chips in the blade)
* Medium grit - grits from #1000 to #2000 (used mainly for restoring blade keenness)
* Super fine grit - grits of # 3000 or above (used for finishing honing of the blade edge)
Medium grit whetstones are suitable for routine maintenance. A medium grit whetstone of about #1000 to #2000 grit is best for the GLOBAL range.

How to sharpen your knife

1) Soak the whole whetstone in water (for about 20 minutes), allowing ample moisture to soak in. 2) Lay down a damp towel on a flat surface of a table and place the whetstone on it so that it does not move.
3) Hold the knife handle firmly with the blade edge facing towards you. Hold the knife steady by placing the thumb on the blade side. Have your fingers of other hand also lightly placed on the blade side. Position the knife so that it may get in contact with the whetstone, from tip to heel. 4) Hold the knife at an angle of approximately 15 degrees against the whetstone (about the thickness of one or two 10 yen coins). A flat blade is obtained by maintaining a steady angle and grip.
5) Move the knife gently back and forth with a constant rhythm. Using the maximum area of whetstone, slide the blade away from you, from the tip to the heel. When drawing it back, pull the blade gently back towards you. 6) Touch the edge of the blade with your finger. If sharpened correctly, there should be burrs and you feel the blade is rough. Make sure the burrs are dispersed evenly across the knife.
8) If the knife is chipped, we recommend that you follow the procedures mentioned above, starting with a rough grit whetstone, followed by a medium grit and then a super fine grit whetstone. It would be sufficient to use only the medium grit whetstone followed by the super fine grit whetstone for normal sharpening.

For double-beveled knives
Sharpen the knife with a ratio of 6:4 for front side and back side. When burrs appear on the reverse side, sharpen the knife so that the burrs disappear.

For single-beveled knives
Firstly, sharpen the side that has a blade edge and when burrs appear, lay the reverse side of the knife flat against the whetstone and keep sharpening both sides in turn until the burrs disappear.
7) When burrs have appeared, sharpen the other side. Turn the knife, hold it by your other hand and pull it towards you.

Precautions when sharpening your knife

* Do not put unnecessary pressure on the blade when sharpening it. You may injure your hands by the staggering blade if unnecessary pressure is put on it.
* Maintain the same angle of the blade against the whetstone.If the knife is not held steady during sharpening, the blade may be damaged.
* Please take care to avoid abrasion when the fingers rub against the whetstone surface.

Maintenance of your whetstone
Grooves will be formed on whetstones by continual use. They must be leveled regularly with a "leveling stone". So long as these grooves remain, your knife's blade can't be sharpened correctly and may be damaged.