Not really. Jnats produce the most noticeable results on carbon steels, such as Aogami or Shirogami, where their very fine mud produces a refined finish. On stainless steels like VG-10 or SG2, they work, but the difference compared to a good synthetic stone is less noticeable. For common stainless steel blades, the synthetic stone remains more suitable. Jnats are therefore reserved for carbon steel knives or a fine finish on a blade that has already been mastered.
Natural Japanese whetstone
Natural or synthetic: which stone should you choose for your Japanese knife?
How to use a natural Japanese whetstone
A few principles guide a session on a natural stone:
- moisten the surface rather than submerging the stone, as most hard Jnats do not need immersion;
- maintain a consistent angle, generally between 10 and 17 degrees depending on the fineness of the blade;
- work in small circles or in long, slow strokes to gradually form the slurry;
- let the stone dry completely before storing it.
Sharpening a knife with a natural stone: levels and progressions
A Jnat is usually used at the end of the sharpening sequence, after coarse and medium synthetic grits. For an Aogami knife, a typical progression involves a 400-grit stone for repairs, followed by a 1000-grit stone to reshape the edge, before finishing with the Jnat. When used on its own, it is best suited for maintaining an already established edge. Stay Sharp recommends mastering a 1000-grit synthetic stone before investing in a natural stone.
Stay Sharp sharpening service: when to entrust your knives to a specialist
Sharpening on a natural stone requires time, practice, and a good understanding of the blade: it cannot be mastered in a single session. In the meantime, the sharpening service at Stay Sharp takes over using water stones, in-store in Montreal and Quebec City, or by mail across Canada. There, the knives are sharpened by hand by the team. To improve your own skills, the sharpening course offers guided instruction.
Frequently Asked Questions
Is a natural Japanese whetstone suitable for all knives?
How to recognize the quality of a natural Japanese stone before buying?
The origin provides an initial clue: Kyoto's historic deposits, such as Nakayama, Okudo, or Ohira, are the most renowned, even though several mines have closed. Next, examine the surface, which should be uniform and free of cracks; its color ranges from blue-gray to beige depending on its origin. Weight also matters: a stone that is very light for its size is often softer, wears down more quickly, and is more likely to develop an uneven surface.
What is the difference between a natural and a synthetic Japanese water whetstone?
Everything depends on the consistency of the grit. A synthetic stone has a factory-calibrated grit size, while a Jnat offers a naturally variable grit. Its mud contains particles of various sizes, which produces a progressive polishing effect. The synthetic stone, being more predictable and less fragile, is better suited for routine maintenance. The Jnat is intended for finishing and advanced sharpeners, particularly on hard carbon steels.
How long should a natural Japanese stone be soaked before use?
Generally, it is not soaked. While some synthetic stones require five to ten minutes of immersion, most hard Jnats only need the surface moistened before and during sharpening. Softer natural stones can tolerate light, continuous wetting. As a general rule, do not leave a Jnat in water for more than a few seconds, as excess water can weaken its structure and lead to fine cracks over time.
Does a natural sharpening stone wear out faster than a synthetic one?
Often, yes. Jnats are generally softer than graded synthetics, such as Shapton ceramics. This softness speeds up the formation of the sludge, which is an advantage, but also wears down the surface more quickly. Regular flattening compensates for this wear. When properly maintained, a natural stone can last for decades: its rarity and price are due to its origin and limited extraction, rather than any particular fragility.