The biface whetstone is made using two different grains (1000 and 3000) in order to maintain the sharpness and accuracy of the blades. Sharpen blades first using the rougher 1000 side, then finishing up with the finer 3000 side will help maintain them indefinitely.
3000 was created using a special technique that combines the materials found in both natural and artificial stones allowing one to sharpen knives with extreme precision.
Sharpening a knife involves quite literally cutting its surface by means of grains aligned on the whetstone's surface. Today the two kinds of materials used —artificial and natural stone— each have their advantages and disadvantages.
Artificial stone:
In the most common kinds of artificial stone available today the grains are bound by means of "glue." This artificial binding process has the advantage of distributing the grains evenly over the surface. However, because the "glue" tends to melt and run when the blade is being sharpened, there is a "slipping effect," i.e. the blade heats up and slides over the surface. As a result it may lose some of its rigidity.
Natural Stone:
Natural stones hewn from rock do not heat up or cause the blade to slide. But the grains of such stones lack homogeneity in size and distribution and thus do not sharpen evenly.
The 3000 whetstone was created to combine the advantages of both kinds of stone. No binding agent was used in its fabrication. A novel technique using thermal energy makes it possible to distribute grains evenly over its surface so that there is no risk of slippage or heating up when you sharpen your knives. As a result they will keep their fine cutting edge for a lifetime.
