http://www.japaneseknifeimports.com/gesshin-1/gesshin-toishi/gesshin-600-splash-and-go-stone.html
This stone is the result of many months of testing and a number of prototypes.
The Gesshin 600 Grit stone is a splash and go stone. However, it works best after a quick 1-2 minute soak. This stone is medium hard, relatively fast cutting, and leaves a very nice finish and even for a 600 grit stone. It also resists dishing pretty well. This stone works well as a coarse stone to start off your sharpening or for somewhat larger repairs. It cuts well on all kinds of steel i have tested it on, from white steel to ZDP-189. It works best when you allow the togidoro (mud and swarf from sharpening) to build up a tiny bit. Because of the level of finish this stone leaves, it is possible to go to a higher grit stone pretty quickly from this. For example, this stone works very well in a 2 stone setup with the Gesshin 6000.
For a long time, we have been working on producing a good coarse splash and go stone, and we are very happy with the results in this stone.
Though this stone is splash and go, it can be soaked in water. If you should choose to dry it out, it should be allowed to dry in cool, well ventilated area away from direct sunlight.