Amakusa Tokubinsui Red Natural Medium Stone ~800-1000 grit Nakato Type 15~2200 Grams

Tokubinsui are analogous to 800 to 1000 grit but cannot be graded in the same way synthetic stones are. They are coarser and slightly less homogenous than white Amakusa (approximately 1200 grit) but finer and more homogenous than the red and white striped Amakusa Torato (tiger stone). 

Tokubinsui vary in appearance a bit but generally have a white background with red patches, white and black dots with a good amount of pores. Their hardness is more homogenous throughout the stone than the Torato which can have harder and softer patches. These cut differently with lots of water and with a wet or dryer mud.

These are great for quickly working up an edge on carbon steel and agreeable stainless steel knives. Some very wear resistant steels can be slower to sharpen on these. Some knives are better served by synthetic medium stones which can be more predictable on wear resistant steels but these are fun to work with.

As an added bonus these big type 15 stones are great for keeping you stationary in strong winds. Type 15 refers to the number of stones that would be carried on the back in the traditional style.  

Amakusa volcanic tuff stones were formed from pyroclastic flows of molten ash and can come in different coarsenesses depending on the geology. They are not sedimentary stones like most tennen toishi and are quite durable and do fine with long soak times. Use a stone flattnener to raise a little slurry and keep the slurry wet during sharpening to get a slightly more aggressive cut from this stone. 

Stones vary slightly in size but are roughly 2020 grams approx 215x70x60mm