Vintage Aoto Tomo 

Aoto Tomo 1

 Aoto = Blue Stone

This piece of Aoto was retrieved from an old tool box owned by a retired woodworker. Aoto translates to ‘blue-stone’ – and these stones are very popular with knife sharpeners and carpenters. These stones were first mined in the early 1300s, during the Muromachi era, but the famous quarries have been closed since the mid 1980s. 

Many Aoto were quarried in Tanba, which was a province and also a city in Kyoto Prefecture, Japan. It is said that the finest examples were mined in the Kouzaki district of Kameoka. 

Aoto can be hard, soft, fine, coarse, fast, slow – etc. Many inexpensive Aoto are very dry and/or prone to having toxic inclusions. However, there are higher-quality Aoto that are quite good and free of issues. Generally speaking – the softer the Aoto, the more coarse it is. The hardest Aoto are usually a bit slow while being a bit finer. Additionally – working the slurry on a harder stone seems to allow a greater level of refinement.   

This small Aoto Nubbin is on the softer side of the scale, but it also seems to be a bit finer than all of the softer Aoto I’ve experienced. Relatively speaking, I’d guess this stone’s slurry to be in the 3k range but after the slurry is exhausted, striations on the bevel appear to be like what I’d see after working it on a 5k stone.   

I’ve slurried this on a harder Awase several times – it generates a nice mid-grit slurry that will break down nicely. What I’m hoping for, is to pair it up with a full size stone that’s a bit harder than most. Until then – it’ll sit patiently in the Tomo box. 

I’ve sealed the sides with Cashew lacquer and I labeled it on one side with a sharpie so I don’t mix it up with other stones. 

Approx. Dimensions: 1.5 x 1.5 x 1.0 / 38 x 38 x 25 mm

Weight: 2.8 oz / 80 g


© Keith V Johnson 2014 - 2018