If all things are equal: a grit rich or silica rich stone will remove a measured amount of steel
faster than a grit poor stone will.
A soft grit rich stone will remove a measured amount of steel faster than a grit poor hard
stone.
Like wise if all things are equal: a coarse stone will remove a measured amount of steel
faster than a finer stone will.
In the same vain a slurried stone will remove steel faster than a non slurried stone will.
And again a stone used under running water (that rinses away any loose grit/slurry
particles) will act finer than a stone with standing water, with or without a slurry.
Japanese natural sharpening stones are unique in the world of sharpening for handfuls of
reasons and one of those is their ability to take on different characteristics while in a state of
being used dry, wet, with a slurry or under running water like at your kitchen sink.
One example of this would be that if any one particular high Hard Level Jnat (Japanese
Natural) is used dry and without water their sharpening qualities are diminished and they will
act more like a burnishing stone, but if that same high hardness level stone is used wet it will
act as an abrasive stone. The same goes for coarse stones. Japanese awase-do (aka
awase-to, tennen toishi) really only cut with advanced actions when wet.
And about to slurry or not to slurry. A slurry comprised of loosely bound grit particles
suspended in water, often acting as bundles of bound grit will act coarser and cut faster
strictly depending upon the mechanical action that created the slurry. A #400 diamond plate
will make a coarser acting slurry than a #1200 diamond plate. A nagura or slurry stone cut
from a similar piece of tennen toishi can if harder than the base stones encourage the base
stone to contribute slurry more freely, or if the nagura is softer it will itself provide the
majority of slurry particles. This is the principle for which the Nagura Progression System is
based and this system will only work marginally well with other base synthetic or natural
stones like Coticules, Arkansas and the other slate stones.The Japanese dedicated natural
nagura tend to favor being paired with the natural awasedo found near Kyoto because both
the base and nagura components will encourage the crush of the clays that release the
silica grit of each other.
In all the world the Japanese tennen toishi are unique because of the slurry component and
the way it can be exploited. For centuries the clay binders that comprise the glue that holds
the stones grit in place has been manipulated by sword polishers, carpenters and barbers to
suit their needs and requirements. No other stone will react with such characteristic and
predictable ways as the natural stones that the mountains in and around Kyoto offer.
Copyrighted 2017© by Alex Gilmore TheJapanStone
cannot be duplicated without written permission
