The knives I use in this review are the Nenox 230 mm sujihiki, purportedly a VG1 steel knife and a white #2 steel Nubatama deba that was rejected by the knifemaker as not meeting his extremely high standards (grind error at the tip on the back). It is an otherwise well constructed knife, but without Kanji or a handle. I'm using it as a practice knife for sharpening demos. It was previously sharpened with the 4k Nubatama Bamboo in an earlier video. It behaves in a similar manner to the 4k Bamboo, but finer in every way. The mud is a bit finer. Porosity is similar, so the stone can be treated as a near splash and go with no presoaking required. The edge is more refined. The jigane or soft cladding of the knife increases further in luster continuing to remove the natural stone finish to some degree. The resultant edge is extremely fine and SHARP with excellent slice and push cutting performance. Fairly hard stone. No concern with edge trailing or leading strokes.
The stone has excellent abrasive power and should work well both with naturals and be able to span a wide gap allowing it to work well with coarser stones in the 1 to 2k range if desired.
Quick cutting, doesn't glaze with adequate water (hydration) Harder than the Naniwa superstones. Generate a very refined mud. A quiet consistent stone, and a pleasure to use.
Another wonderful Nubatama stone !!