Combination 1000 / 4000 stone with fast cutting hard ceramic 1000 grit yellow marble and fine finishing resinoid 4000 stone. Good as a maintenance stone for double bevel Japanese and western knives, the 4000 finish is a good middle ground fine finish for a wide variety of knives. This hard marbled yellow 1000 grit stone is very fast cutting and well suited to bring up an edge on a fairly dull edge.
Bernal Cutlery Takarazukushi ceramic stones are made in Japan with alumina and zircon abrasive particles that are baked with ceramics creating a fused porous stone. Harder Takarazukushi stones tend to cut deeper and faster than the semi-soft stones on double bevel knives made with wear resistant steels. Semi-soft Takarazukushis stones cut wide bevels very nicely and leave shallower easier to finish scratches than the harder stones however both hard and semi-soft work on both.
Ceramic stones will not come apart with longer soaking periods (although water should be changed) resinoid stones should not be left to soak indefinitely, and both should be allowed to dry outside of sun and wind and not allowed to freeze wet.
It is important not to let these soak for longer than 15 minutes at a stretch for longevity.