The Gesshin™ 4000 Grit Sharpening Stone is an awesome shiage toishi (finishing stone). Like this rest of the Gesshin™ stones, I have been testing this one for quite some time now. This is my favorite stone in the 3000-6000 grit range of any stone I have used up to this point. It has amazing feedback, it is extremely fast cutting, is not too hard for kitchen knives, leaves a very good finish, and resists dishing well. Like the Gesshin™ 400 and 2000, this stone works well on all kinds of steel, from simple carbon to high tech powdered stainless. This stone can be used as your final stone or as a step up to something in the 8000+ grit range. You can easily jump from a medium grit stone (or even one as low as 700 grit) to this one, and, when you’ve finished sharpening on this stone, you will be left with a very nice toothy, yet refined edge. I have been using this as a finishing stone for many knives now days. This stone needs to be soaked at least 15 minutes before use (30 or more is ideal). I leave mine in water all of the time, so it is ready to go whenever I need it. If you do leave your stone in water, please change the water regularly. When drying out this stone or any others, do so out of the sunlight in a well-ventilated area.