The Naniwa Super Stone series is now called the "Sharpening Stone" series for some reason. Naniwa says they improved them by tightly controlling the grit sizes for more consistent and accurate cutting. These stones are resin impregnated stones that are fast cutting and silky smooth. Great for kitchen knives or razors. The super stones are splash and go stones and don't require soaking. Perma soaking these stones is not recommended.