The Gesshin Jinzo Aoto (synthetic aoto) is a very soft medium grit stone designed to leave a very nice, smooth, even finish on wide bevel and single bevel knives, while providing great contrast between the hagane (core steel) and jigane (cladding). People often go to natural stones for this kind of finish, but this synthetic stone offers the best looking finish i have seen from a synthetic stone with the greatest ease (keep in mind that this is not a finishing stone... its a medium grit stone, so there may be some visible scratch pattern... however, it is often very smooth and uniform). The key to using this stone is working up mud. Because it is very soft, it is very muddy. Even just a little bit of sharpening will create a large amount of mud. The more mud you can use, and the less pressure you sharpen with, the better your results will be.
This stone also happens to be great for very hard and wear resistant steels. Because of its softeness, it releases a lot of fresh abrasive very quickly, thus helping the cutting speed. We especailly recommend this as a great medium grit stone for honyaki knives and similar types of steel.
Because this stone is very soft, it is important to try and use the entire surface of the stone more evenly. Also, you may find it necesary to flatten a bit more than harder stones. The finish this stone leaves is worth it though.
This stone can be stored in water, but please be careful when drying it out, as that is the most delicate time for the stone. It should be allowed to dry in cool, well ventilated area away from direct sunlight, so as to dry slowly and evenly. For soaking, this stone works best with 5 minutes of soaking.