Nubatama Ume 1K. 205mm x 75mm x 25mm. This is one of several 1000 grit stones available among the Nubatama Synthetic Japanese Waterstones. This particular one is part of the Ume or plum series and is the hard version. Most notable for it's georgeous speckled pattern, it is a particularly beautiful stone that sharpens as well as it looks. A popular synthetic stone used by sword polishers, it also works superbly with knives. In this video I use it to help refine the geometry of a carbon steel kurouchi nakiri with a zero grind edge - the edge is continuous with the side of the knife. More porous than a Shapton stone, it is comparable in porosity to Choceras and after a brief run under the tap of a couple minutes stays saturated fairly quickly. Rapidly abrades, producing a fine dark mud loaded with swarf. Doesn't load up, keeps cutting . Maintains a noise level comparable to other 1k stones, although a bit higher in pitch. Leaves an excellent hazy edge and appears to give a differential finish between the soft cladding and hard core steel on this carbon steel knife. I conclude by demonstrating the knife easily both slice and push cutting standard copy paper.
This is a pleasurable stone to work. It is fairly hard. There is no danger in cutting into the stone, so edge leading and trailing strokes are not a problem at all. Highly recommended for amateur and pro alike, whether this is your first stone or your thousandth.
I really like this stone. It cuts well,is hard and has great feedback.
I took my new stone on a test drive yesterday and WOW that sucker was incredible. The swarthy mud it creates while no hint of loading absolutely was great!
Now my Shapton Glass 1K is going to be very lonely . . .
I was also surprised to find the edges already chamfered. I still flattened it including taking the edges off,but probably didnít have to as it was already flat and edges were already treated.
I sharpened two Shun knives (VG-Max Steel) and some nice-but-German paring knife. Both Shuns had chips and that stone not only quickly raised a burr,but it was also aggressive enough to get those chips out without using a coarser stone (if the steel was harder,I probably would have pulled out something coarser).
The polish was consistent and cloudy reminding me more of a natural stone instead of synthetic.