Seki Magoroku Whetstone Coarse 400 Grit

Whetstone type: Coarse

Typical use: Repairing chips or cracks and straightening the blade edge.

Use to remove small chips or repair the blade shape. The stronger grinding power allows you to sharpen knives smoothly. It can be used to remove rust.

Includes a multifunctional storage case. The lid is designed to hold water for soaking the whetstone prior to use, and the base has non-slip feet to provide a steady platform for sharpening. Suitable for sharpening and maintaining all knives, including high spec blades.

184 x 64 x 15mm (L/W/H)

Made in Japan.

Using your Kai whetstone

What grit whetstone is best?

Typically a coarse whetstone, 250 to 400 grit, will remove material quickly. This is useful for repairing chips or other imperfections.

A medium grit whetstone, typically 1000 to 2000 grit, is suitable for sharpening most knives that have a blade in reasonable but dull condition.

A fine to very fine whetstone, around 4,000 to 8,000 grit is used for finely sharpening, finishing and polishing your blade to a mirror like finish.

Soak your whetstone

The whetstone should first be soaked in water for about 10 minutes before using it. Thereafter place on a slipfree surface and ensure the stone is kept slightly wet during the grinding process by dribbling some water on the surface.  

How to sharpen with your whetstone

Double bevel blades (e.g. Shun Classic, Premier)

Grind the knife with a 15° angle to the whetstone, moving the blade with light pressure toward and away from your body. Repeat this process until you can feel a fine burr.

This should be repeated proportionally on all parts of the blade. It is important to grind both sides of the blade equally to regain a symmetrically sharpened knife.

To remove the burr formed along the blade as a result of sharpening, place a piece of newspaper on a flat surface and holding the knife at a similar angle used on the whetstone, swipe the blade sideways left and right across newspaper.  Once the burr is removed, you will feel a smooth edge along the blade.

After sharpening carefully wash, dry, and safely store your knife.

Single bevel blades (e.g. Kai Wasabi)

Place the ground side first on the whetstone. Make sure that you use the angle recommended by the manufacturer. Grind the knife with a 45° angle to the whetstone, moving the blade with light pressure away from and toward your body. Repeat this process until you feel a fine burr.

Once the ground side is done, turnover the knife and repeat the process as described above on the hollow-ground side but less often – 1/10 will do.

To remove the burr formed along the blade as a result of sharpening, place a piece of newspaper on a flat surface and holding the knife at a similar angle used on the whetstone, swipe the blade sideways left and right across newspaper.  Once the burr is removed, you will only feel a smooth edge along the blade.

After sharpening carefully wash, dry, and safely store your knife.

For further guidance, the video below has some useful instructions: