The fundamental difference between Western style knives and their Japanese counterparts, is the fact, that the Western knife is sharpened on both sides of the blade. They therefore have what is called a symmetrical bevel. This obviously has an impact on the way the Western knife is sharpened. 
When choosing a knife sharpener for western style knives, you need to ensure that the tool is able to sharpen both sides of the blade.
You will also hear much about the angle of an edge when it comes to sharpening. With a Western knife, you must pay attention to the combined angle of each edge is the overall angle. Factory edges for Western knives range between 18 to 28 degrees. It is a figure far higher than that of the average Japanese style knife.
Western style knives are curved more
Western style knives also differ to Japanese in that many designs are curved along the blade. You utilise this design feature every time you rock your knife to and fro in a chopping action. The curve allows you to apply different amounts of pressure to specific areas of the blade.
This curved shape of Western style knives obviously means that you should check that it has the facility to sharpen your knife all the way along the curved edge when choosing which knife sharpener to buy.
The blade thickness is another difference between both knife styles. Traditionally, Western style knives are built using softer steel. In order to give the knife the required density and strength, more material is required. As such, you will often find that a Western style knife is more robust.
The softer steel used in Western knives does means, that the edges become dull faster than the average Japanese knife. Heavy use will see imperfections appear along the blade. However, the fact the material is softer, means most Western style knives can be sharpened with great effect.
Japanese Style Knives
vs Western style knife
If you have read the section above, you will already know that the biggest difference between a Japanese style and western style knife, is the fact the Japanese knife has a single bevel – in other words, the blade is only sharpened on one side.
Why are Japanese style knives sharper?
Single bevel angle on Japanese-style knives, they are often sharper than their western style counterparts. Japanese knives can have a bevel angle as low as 5 degrees.
The most important factor to look out for when choosing a sharpener for Japanese style knives is that you have control over which side of the blade you are sharpening. If the sharpener automatically sharpens both edges of the blade, you will clearly ruin your knife.
As we have already mentioned, Japanese knives are generally made from harder steel than western knives. This allows for the edges to hold sharper for longer.
While the blade is able to withstand wear and tear to a greater degree than western knives, the harder steel can be brittle. It is imperative that you use the correct type of Japanese knife for individual tasks.
Whereas a western chef’s knife may be able to cut through a chicken bone, doing so with a Japanese chef’s knife could see you ruin the edge.
Japanese style knives also differ in that the shape of the blade is very rarely curved. Being long and straight, you should be careful to check that any knife sharpener you buy can efficiently sharpen knives of this shape.
