How to sharpen
Sharpen once every few months, depending on use.
There are various whetstones such as rough, intermediate, or finishing, but intermediate stones are good enough for every day use.
Knife sharpening basics video – double bevel Japanese kitchen knives (English sub)
Enlarged picture of the tip
1. When new, the knife cuts well.
2. After long use, it becomes blunt and difficult to cut.
3. After sharpening the cutting edge, the blade is sharp again.
When to sharpen knives
Having a lot of crumbs | Not cutting a tomato smoothly | Crying when cutting an onion
Your knife would be less sharp if you use it every day. Especially, it would get dull easily with a plastic cutting board. Wooden ones would keep your knife sharp for longer.
Preparing a whetstone
Make your whetstone flat by using a flatting stone. If your knife has large chips or cracks, rough whetstones (#400) are useful. However for daily use, intermediate stones (#800) are good enough. Please be careful not to move the stone. Use a wet cloth under it.
Put your stone in water for about 20 minutes before using it. Please do not put your wooden base in water. It may lose its shape.
How to sharpen
1. Sharpen several parts
If the blade length is about 15cm, it is good to sharpen three parts: tip, middle, and heel.
Seen from above
Keep the angle constant throughout sharpening. About 45 degrees to the whetstone.
Side view of sharpening angle
Double edged knives such as Santoku, Gyuto or Petty
Sharpening at the angle of three 10-yen coins(about 15 degrees).
Single edged knives such as Deba, Yanagiba or Ajikiri
Sharpening the bevel side.
3. Sharpening one side
Hold the knife firmly, place your fingers on the part you’ll sharpen. Push and pull your knife gently and slowly with the cutting edge facing you. The muddy liquid that comes out helps to sharpen the blade, so do not wash it away.
4. Check a burr
After your knife gets a burr, sharpen the other parts. Sharpen the other side after the knife has the burr along the entire edge.
5. Sharpen the other side
Double edged knives: sharpen your knife at around 15 to 20 degrees until it gets a burr.
Single edged knives: put the entire back side on the whetstone, and sharpen it lightly to remove a burr.
Sharpen your knife with a finishing stone (Repeat the above steps No.3-5)
If you do not have any finishing stones, sharpen both sides again to put an edge. Sharpen your knife several times lightly at around 15 to 20 degrees to remove the burr.
7. Clean your knife
After sharpening, wash your knife and wipe it with a dry cloth.