Miyabi is a Japanese knife company owned by the Zwilling Group of Germany. Zwilling, of course, also owns J. A. Henckels.
Miyabi, like Shun, uses a “supersteel” to make their knives. According to the Miyabi website, it is “SG2 micro-carbide powder steel protected by 100 layers of (softer but tougher) steel.” Then it is hardened to Rockwell C value of 63.
The 6000 series is even more extreme: “The core, made from ultra-hard MC63 micro carbide powder steel, is encased in two other steel layers featuring a hand hammered finish known in Japanese as Tsuchime. The CRYODUR blades are hardened in a special process (including ice-hardening at -196 °C), making them extremely hard (approx. 66 HRC).”
So it seems these Miyabi steels are even harder than Shun, which is hardened to Rockwell C 61.
All this means it is virtually impossible for a homeowner to sharpen Miyabi knives. However, I easily sharpen them on my water-cooled 90 rpm Tormek with my CBN (cubic boron nitride) wheels and finish off with various grits of diamond paste. This means your Miyabi will be twice as sharp as when brand new, and only minimal steel is removed to get it that sharp.
(A new Miyabi typically is around 200 BESS).