1. Large Green Aoto.
Those are no longer carried by Maksim (JNS), but are awesome natural stones. The stone is a bit finer than the Red Aoto, I'd say in the 3-4k range.
It is great touch up stone, it is fast and it leaves very uniform finish. Sides are lacquered, the dark spots are water.
PRICE= $450, shipped in US, buyer add 3% PP fees.
2. Ohira Renge Suita koppa
A ton of renge in this stone, it is a finisher that produces a very fine uniform finish. The stone is hard but not challenging to use. Thickness 35mm.
Those are nor really hard to find, and very expensive, I believe Maksim does not carry many of them as good quality at reasonable price is hard to find.
Price= $450 shipped in US, buyer add 3% PP fees.