Where is the daodao 4 whetstone? How to use the martial arts 4 whetstone Raiders

"Shidao 4" where to buy whetstone? How to use the sharpening stone in "Baidao 4"? Many players don't know much about this, but don't worry, the following system is a series of tips and tricks for you to share the skills and tips. I hope everyone likes it.
[Horsestone purchase location] Generally speaking, the smelting house (forging smelting house) is for sale. The small vendors in the port seem to have sold it. Anyway, you will see it everywhere. Sometimes the degree of security is reduced, the goods are not sold, and the whetstone can be seen after the improvement. [How to use the sharpening stone] After pulling out the knife, select the sharpening stone with the left and right direction keys, then use the sharpening stone with the up and down keys! But it is best to find a place where no one is, otherwise it is likely to be mistaken by passersby. You have to attack him!