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Sharpening

Sharpening

Many sushi chefs sharpen their precious knives at the end of each work day. Edge life versus ease of sharpening - it is up to you to balance these considerations and choose an appropriate knife. However, you should choose a knife that matches your level of sharpening experience and meets your needs. If you are inexperienced with Japanese knives and water stones, try to choose a knife that is easier for you to sharpen.

Why so much sharpening?

All knives must be continually worked against a water stone to be use at their fullest potential. As you familiarize yourself with the stone and knife, you may begin to change the bevel based on your needs.

When should I sharpen?

Ideally, you should sharpen the knife right out of the box. This will produce the strongest edge and is especially necessary for traditional Japanese knives. We recommend that customers sharpen their knives before they become too dull. Sharpening a very dull knife will require much more time.

Diamond Stones

Diamond stones are becoming popular with professionals. They require less maintenance and should never be soaked. A light splashing of water is all that is required, making them convenient to use in a busy kitchen. Diamond stones allow for very quick sharpening but we do not recommend them for inexperienced users. They are abrasive and can remove a large amount of material from knives. We recommend applying very light pressure for the first 40 uses.

Natural Sharpening Stones

In Japan, there is a market for natural sharpening stones geared toward high level craftsmen and woodworkers. These stones must be carefully selected from the mountain, hand quarried, hand cut, and hand polished, which often makes them extremely expensive. Korin carries a variety of natural stones and can recommend a stone to match a particular knife. However, we do not recommend natural stones for inexperienced users. We ask customers to understand the risks involved in purchasing a natural stone, and that we cannot guarantee natural stones.

Knife Stone Care

Soak stones for the appropriate length of time according to the grit.

Rough Stones (#220 - #400): Soak up to 10 minutes
Medium Stones (#800 - #2000): Should be soaked for 10 minutes or more.
Fine and Finishing (#2000 – #12,000): Splash only. Never soak.
Diamond Stones: Splash only. Never Soak
Two-sided Stones: Soak the medium stone half. Never soak the finish stone side. Failure to do so will result in cracking.

Stones can be fragile and should never be over-soaked. Over-soaking will decrease the stone’s quality and make sharpening more difficult. After sharpening, wipe clean and allow to air dry. It is preferable to store stones in a dry towel. Returning a wet stone to its cardboard box can lead to mold growth, which can weaken the stone resulting in cracking or separation.

Knife Sharpening

  1. Soak or splash with water according to the guidelines above.
  2. Put stone on wet cloth or base to stabilize while sharpening.
  3. Hold knife as pictured. Index finger rests on spine and thumb on flat of blade, and three remaining fingers grasp handle.
  4. Start with knife tip. Use two or three fingers of left hand to press edge of blade to stone.
  5. Keep a firm grip on the knife, with shoulders square to the stone and upper body relaxed. Press edge of blade to stone and push along stone, exerting pressure as you move forward and releasing pressure as you return blade to starting position.
  6. Repeat this procedure, pressing the edge closely to the stone and sharpening a bit of the edge at a time until you feel a slight, even burr along the entire edge.
  7. Once you have a burr, reverse the blade. Start with the tip. Exert more pressure on the downward stroke and remove burr, or establish a double-sided edge if desired.

Japanese-Style Knives (Yanagi, Takobiki, Usuba, Kamagata Usuba, Deba Knives)

1. Sharpen the entire cutting edge until there is a slight and even burr on the reverse side.

2. Place the blade perpendicular to and flat against the stone. Remove the burr with your middle and index finger gently pressing the edge to the stone and your thumb gently pressing the spine. Pressing both sides of the blade preserves the slightly concave shape of the reverse side of the blade and helps make future sharpening possible. Think of the motion as if you are "pushing" water off the stone.

3. Flip the blade over again and sharpen the shinogi line by moving your fingers away from the edge and pressing just below the middle of the blade. For optimum performance, it is very important to preserve the original shinogi line.

Western-Style Knives

1. Note the angle of knife to stone while sharpening.

2. Angle the knife to establish the cutting edge. A 10º-20º angle is suggested. A smaller angle will make a sharper, but weaker cutting edge. You can use two pennies to gauge an approximately 12º angle. Use this trick to help measure a consistent angle until you feel confident in sharpening.