►Sharpeners I use in this video (Amazon affiliates links)
※These sharpeners seem to be sold more expensively outside of Japan. I believe you can find cheaper ones that are decent online as well. Zwilling J.A. Henckels also has good sharpening stones which I have used before. Unlike the ones I used in this video, you don't need to soak it in water to sharpen a knife (but it still needs to be wet).
Sharpening stones come in grits, and these two grits would be enough for a normal household knife. I used grits 1,000, 2,000, 5,000, 8,000, and 12,000 in this video. The higher the number, the finer the sanding and the sharper the knife will be.