Sizes are measured at longest part of the whole stone, not the actual flat surface.

General info given by Tsunesaburo

About Nakayama and Okudo natural stones

Among the natural stones available in Umegahata, Ukyo, Kyoto, these are the highest quality stones available. Sometimes called Tohmon or Higashimon, these are very tight, easier to get the slurry out, and are highly recommended for finishing your chisels and planes.

Simple Q & A

Q:Whats the grit of natural stone?
A:Unlike synthetic stones, natural stones do not have specific grits. Using the slurry containing sharpening particles, which breaks down even finer while sharpening, it's more like lapping using the slurry between the blade and the stone. While synthetic stones put an edge on tool according to their grit, natural stones will give sharper edge the more time you spend sharpening.

Q:Can these stones be soaked in water?
A:No, put some water on top and start sharpening. If you soak them you risk breaking them.

Q:How do you determine the hardness of stone?
A:Put a drop of water on surface and see how long it takes for the stone to suck the water. If the water remains for more than a minute its either a "hard" stone or "tight or condensed" stone. These two should not be confused. What you want is a tight stone.

Q:I sometimes get unlikely scratches on surface.
A:Harder stones are harder to get the slurry out, and while sharpening, the laminated soft iron can sometimes scratch the surface. To avoid this use the nagura to get the some slurry out before sharpening. If the stone stops releasing slurry while sharpening, you can also fix this by using nagura on it.

Q:How do you lap the stone?
A:Either 1000 grit diamond plate or #180 water proof sand paper on flat glass. Both needs water.

Q:When do you use natural stones?
A:After #5000 to #8000 synthetic finisher.

 

Stone#1
Nakayama Tomae
2.6lb 8 1/16" x 2 15/16" x 1 1/4"

Stone#2

Okudo Suita
3.2lb 7 11/16" x 2 3/4" x 1 5/8"

Stone#3
Nakayama Tomae
2.2lb 6 1/2" x 3 1/8" x 1 1/8"

Stone#4
Okudo Suita
2.6lb 7 5/8" x 2 3/4" x 1 3/8"

Stone#5
Sho Honyama
2.4lb 8 1/4" x 3" x 1 1/8"

Stone#6
Okudo Tomae
2.0lb 7 1/4" x 3 1/8" x 1"

Stone#7
Okudo Tomae
2.2lb 5 7/16" x 3 1/8" x 1 6/8"

Stone#8
Nakayama Tomae
1.8lb 7" x 3" x 1 1/16"

Stone#9
Nakayama Tomae
4.6lb 8 1/2" x 4 3/16" x 1 3/4"

Stone#10
Nakayama Tomae
2.8lb 6" x 4 13/16" x 1 1/4"

WARNING

This product can potentially expose you to chemicals including lead, nickel and chromium which are known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warning.ca.gov