Japanese Natural Toishi Whetstone - Umijiyama Suita Renge

This exceptional Japanese whetstone was selected and purchased by us directly from Japan, then thoroughly tested and coated with cashew lacquer on sides and back to protect the stone for long term use. It measures  185 mm (7.28 in) long × 65 mm (2.56 in) wide × 17 mm (0.67 in) thick, and weighs 495g.

Stone Testing Details:

Hardness: LV 4.1
Beautiful Hon Suita from Umajiyama with Renge. This is a rare stone that isn't seen as much these days. It is a hard and fine Suita with a dense feel and beautiful Kiita yellow base. Beautiful aka Renge peak through in patches. 
For razors, water only honing yields fast cutting results that will release a little black swarf. There was no self slurry and the stone has a chalky feel, similar to how some Mikawa Nagura feel. 
Diamond plate slurry speeds up cutting and will remove scratches from medium grit quickly but the resulting edge is aggressive and and will need a bit of work to refine. 
Mikawa Nagura progressions are doable as the stone is just hard enough to capture the full potential of the Nagura without fine, Suita particles mixed in. However, when testing, this yielded a very crisp and aggressive edge so may be worth a shot at trying and refining further. 
For knives, this stone is a wonderful finisher and very fine for Umajiyama Suita. It has an eastern mine type overall feel and performance which is a huge compliment. It leaves a beautiful bright and semi mirror Kasumi with great contrast. 

There is a small area at one corner which should resolve after the stones first lapping.

A photo of the resulting polish left on a high quality Japanese knife is shown.