The Japanese waterstone manufacturer Suehiro, from Niigata Province, makes the Suehiro und Cerax brands. We offer the classic SUEHIRO 6000 grit honing stone and also a 3000 grit stone to bridge between sharpening and honing.
 
We recommend that SUEHIRO stones not be left in their water baths too long. It is enough to put them in five minutes before use. The surface of these stones can erode if they are stored too long in water. This is not really a disadvantage however. It happens because there is relatively little binder in the stones: less binder - so quicker cutting as dull particles come loose and allow the fresh, sharp grit to come into play. Baked of Aluminium oxide added with bond and filler.
 
Waterstones do wear concave with use and require periodic re-flattening.  A flat stone is indispensable for effective sharpening, especially with flat blades like chisels and plane irons.
 
Measurement - 183 x 63 x 20mm