This stone is a perfect bench size stone at 203mm x 88.9mm x 38.1mm.
This stone is wayy too hard for me, and can barely raise it's own slurry. Probably a 5+ on some hardness scale. There is no Maruka stamp, but I TRUST the vendor that I bought it from which was Ai and Om, ( Sister shop of Tosho)
Probably too expensive for me to keep around as I have tested it. You will need a lot of skill to produce an edge with this stone. You can not feel any lines on the stone although it looks to appear like there are some. This stone is not lacquered.
This stone is wayy above my skill level for use, and I'll price it at $550USD shipped USA/CANADA (around the price I bought it for with tax...)
Possible trades I'm into: Knives 240-270mm. ( Something interesting like Heiji, Shig, Kato, or some mighty workhorse knife)
Used once by me, and then lapped with a Atoma 1200. This stone is weighed at ~1400g ( used a bad scale and it went 1380ish)