Amakusa Binsui XXL Natural Coarse Stone Arato ~3000 Grams

Amakusa Binsui coarse stone from Kyushu in an extra large size.

Amakusa Binsui are analogous to 400 grit and are the traditional second stone in a progression after the extra coarse Oomura sandstone in sword sharpening. 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 coarse stones which can be more predictable on wear resistant steels but these are fun to work with and these are great for keeping you stationary in strong winds. 

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. To get a slightly more aggressive cut from this stone use a stone flattnener to raise a little slurry and keep the slurry wet during sharpening. 

Stones vary slightly in size but are roughly 3000 grams and 220x100x60mm