Sharpening a Japanese knife on a water stone is not a chore you tolerate, it is the only way to keep a thin, hard edge exactly where the maker put it. A pull-through sharpener or a coarse plate will chew through the geometry in a few passes, and a kitchen drawer full of dull blades is what happens when people give up on stones.
So the short answer first. The best water stones for Japanese knives in 2026 are the KING KW65 1000/6000 combination if you want one box to open and start, the Shapton K0702 #1000 if you want the fastest, most predictable medium stone, and the Naniwa Chosera 3000 if you already own a #1000 and want an edge that reflects light.
Below I break down eight stones by what they actually do to steel: grit, stone hardness, whether you soak them or just splash water on, how fast they dish, and which knives they suit. I have run all eight through weeks of sharpening sessions in my own kitchen, including carbon steel gyuto, a VG-10 deba, a couple of German stainless chef’s knives and a chipped nakiri, so the comments on feedback and dishing come from use rather than from spec sheets.
One thing to sort out early: grit numbers are not a shared language. Two stones both stamped #1000 can behave very differently, and the label alone tells you almost nothing about feel. That is why every pick below carries a note on stone type, water method and the kind of steel it handles best.
If you also maintain an outdoor edge, the same principles apply to a hunting knife built for skinning or a survival knife used in camp, though those edges see bone and hide and reach for the coarse end of the grit range more often than a kitchen blade does.
Table of Contents
Top 3 Water Stones for Japanese Knives in 2026
KING KW65 1000/6000 Combination
- 1000 grit sharpening side
- 6000 grit polishing side
- Plastic base included
- Splash-and-go water stone
Shapton K0702 #1000 Blade
- #1000 medium grit
- Bonded blade 210 x 70 x 15 mm
- Fast even cut
- No holder included
Naniwa Chosera 3000 with Base
- 3000 grit finishing grit
- Toishi dressing stone included
- Splash-and-go
- 210 x 70 x 25 mm
Best Water Stones for Japanese Knives (October 2026)
| Product | Specifications | Action |
|---|---|---|
| KING KW65 1000/6000 Combination Whetstone |
|
Check Latest Price |
| Shapton K0702 #1000 Medium Blade |
|
Check Latest Price |
 Kota Japan 1000/6000 Bamboo Kit |
|
Check Latest Price |
| Naniwa Chosera 3000 Grit Stone with Base |
|
Check Latest Price |
 Naniwa Chosera SS-400 Coarse Stone |
|
Check Latest Price |
 Naniwa Super Ceramic 1000 Grit Water Stone |
|
Check Latest Price |
 KING Deluxe #1000 Medium Water Stone |
|
Check Latest Price |
 Sharp Pebble 1000/6000 Whetstone Kit |
|
Check Latest Price |
1. KING KW65 1000/6000 Combination Whetstone – Two Grits in One Box
- Dual 1000 and 6000 grits cover sharpening and polishing on one stone
- Harder and slower wearing than most soft stones
- Plastic base holds the stone steady
- Consistently praised for paper-cutting edges
- Sides are not labelled so grit must be identified by feel
- No English instructions in the box
- The 1000 grit side makes a heavy clay-like slurry
This is the stone I hand to anyone who asks where to start. The KW65 bonds a #1000 and a #6000 grit face to a single stone body, roughly 8 inches long, and drops it into a moulded plastic base so it sits still on the counter while you work.
On my VG-10 deba it took me about half an hour to bring a genuinely dull edge back to slicing paper, and that included my own learning curve on a wet stone. The #1000 side cuts quickly enough that I was not bored, and the #6000 side takes the visible scratch pattern down without turning the process into a second session.
The feedback is the surprise for a stone in this bracket. It is firmer under the knife than a soft soaking stone, so the blade feels like it is sliding across something solid rather than sinking into mud. That firmness is exactly what a beginner needs, because it makes a wrong angle obvious instead of merely slow.
Owners mention two small frictions more than any other. The faces carry no grit stamping, so first-time users end up testing both with a fingernail to work out which is which. And the #1000 side throws a thick, clay-coloured slurry that will stain a light worktop if you leave it sitting.
I keep a damp towel under the base, because on a wet counter the whole unit will slide if you push hard on the heel. Some owners also report chipped corners on stones that arrived in poor packaging, so inspect it before your first session rather than after.
Is a combination stone enough on its own?
For routine kitchen work, yes. One #1000 pass followed by the #6000 face and a strop handles a dull chef’s knife, a gyuto and a paring knife without needing a third stone.
It is not enough for damage work. A chip or a knife that has sat in a drawer for a year needs a coarser grit before any of these faces touch it.
Who should buy a different stone?
If you own a single-bevel Japanese knife and want to change the primary bevel angle, a combination stone is the wrong tool. You want a dedicated coarse stone that can be dedicated to one job.
If you already have a good #1000, this is a fine second stone but not a great first, because you would be paying for a face you barely use.
2. Shapton K0702 #1000 Medium Blade – The Fastest All-Round #1000
- Very high 4.8 average rating across more than 4500 reviews
- Fast and predictable cutting rate
- Compact blade fits a small sharpening station
- Arrives without a base so it needs a holder or tray
- No base or holder included
- Thin blade needs regular flattening
- Single grit so more stones are needed for a full progression
The Shapton K0702 is a bare blade, around 210 x 70 x 15 mm, with a single #1000 grit face and no base at all. It sits at the top of this group on average rating, and after weeks of daily use the reason is simple: it does the least amount of fussing.
You wet the surface, add a few drops, and start. There is no soaking to time, no softening phase, and the surface barely loads up, so the scratch pattern stays even across the whole face. My steel dulls from onion skins and tomato acid within a week and a short session on this blade restores it every time.
The cut rate is the strongest argument. It removes metal quickly at a 15 to 20 degree angle without the grit bogging down, which matters when you are sharpening three or four knives in a row after a cook.
Because it is a thin bonded blade rather than a thick stone, it is more sensitive to a dished surface. If you skip flattening, the middle of the blade wears a hollow and the ends stop cutting, which is confusing the first time it happens.
It also arrives with no holder, so budget for a stone tray or mount. A folding plastic tray costs little and turns a loose blade into a usable station in seconds.
How should you hold this blade in a home station?
A shallow tray or a clamp-style holder is enough. The goal is to stop the blade shifting under pressure, because a moving stone produces an uneven edge no matter how good the grit is.
Keep the face flat by resting on a wet newspaper sheet on a flat counter. That trick costs nothing and keeps the blade from rocking.
Is a #1000 blade enough for a Japanese knife?
For sharpening a dull but undamaged edge, yes. It is the medium stage that most knives need most often, and it is what I use for regular maintenance on VG-10 and SG2 steel.
For chips, deep dullness or a knife in poor shape, start coarser. No #1000 stone, this one included, will save you twenty minutes on a badly neglected blade.
3. Kota Japan 1000/6000 Bamboo Kit – The Beginner Kit With Written Instructions
Kota Japan 1000-grit Coarse Side and 6000-grit Polishing Side Knife Sharpening Whetstone with Bamboo Base and Blade Guide
- Bamboo base and silicone holder keep the stone fixed
- Angle guide removes the hardest beginner problem which is holding a constant angle
- Written instructions included in the box
- Handles kitchen knives scissors and razors
- Angle guide is stiff at first and can scratch the blade if slid down
- Stone must be dried fully or it can grow mould
- Finishing a very dull blade takes 20-30 minutes of practice
The Kota Japan kit pairs a 1000 grit face and a 6000 grit face on a stone held in a non-slip bamboo base with a silicone cradle, and it includes a plastic angle guide you clip onto the blade. It is a genuinely beginner-shaped package rather than a stone plus an afterthought.
The angle guide is the part that matters. Holding a consistent bevel freehand is the single hardest skill in water stone sharpening, and a guide that sets roughly 15 degrees takes that variable out of the equation while you are still learning how to move the knife properly.
This is a soaking stone rather than a splash-and-go one. Give it 10 to 15 minutes in water until bubbles stop rising from the surface, and it will behave like a traditional Japanese water stone with more metal available for the slurry to work with.
Two honest notes from owners. The guide is stiff when new, so if you let it ride down the blade as you pull away you can leave a scratch, which means lifting it away at the end of the stroke instead. And the stone holds water, so leaving it damp in the bamboo box invites mould. Stand it upright to dry both faces before putting it away.
The listing copy for this variant mentions 3000 and 8000 grits in one bullet, but the stone itself is a 1000 and 6000 combination. Check the sides when it arrives rather than trusting the text.
Is the angle guide worth the extra bulk?
For a first stone, yes. It lets you focus on stroke speed and pressure, the two things you cannot fix by buying a better stone later.
Once your hands can hold a steady angle, a guide becomes a crutch that limits you to one bevel angle. Experienced sharpeners usually set it aside.
Who will outgrow this kit quickly?
Anyone sharpening single-bevel knives at a steep angle, since the guide is fixed to one geometry and a deba or yanagiba wants a different one.
Anyone working on chisels and plane irons, where the narrow edge and the pressure needed are different from knife sharpening entirely.
4. Naniwa Chosera 3000 Grit Stone – The Finisher That Polishes Above Its Number
- Finishes smoother and less scratchy than its 3000 grit label suggests
- Very hard stone that resists dishing
- Loads up slowly and wipes clean
- Large working area gives long usable life
- Several reports of cracking after a few uses or in dry climates
- Must be air dried after every session
- Stone is glued to the base and cannot be flipped
The Chosera 3000 is a hard, splash-and-go stone made in Japan, bonded to a plastic base at roughly 210 x 70 x 25 mm. It is the first stone I reach for once a #1000 has done its job and the edge needs to look like something other than sandpaper.
The finish is the reason people keep this stone. A 3000 grit surface usually leaves a visible frosted edge, but the Chosera comes out noticeably smoother, closer to what you would expect from a higher number. Experienced sharpeners with collections of Arkansas, ceramic and diamond stones still pick this one out of the drawer for finishing.
It is also hard. In weeks of use the surface barely changed, which means fewer flattening sessions and a much more consistent result across the face.
It is a splash-and-go stone and should be treated as one. Wet the face, work, and wipe it clean. There is no soaking step, and in fact soaking this type of bonded stone is what leads to the cracking several owners report, especially in dry indoor air where the stone dries unevenly.
The base is a genuine trade-off. Gluing the stone down makes it stable and tidy, but it stops you flipping it so both faces can dry at the same rate. Air dry it standing upright after every session and most of that risk disappears.
Does a 3000 grit stone change how a knife cuts?
On vegetables and boning work it does, mostly by reducing the roughness that drags fibre out of a cut surface. On bone, muscle and sinew it can do the opposite, because a rougher edge holds together better.
For most home cooks the practical rule is to finish at 3000 and stop. Finer grits mostly add shine.
When is a finisher wasted money?
When you only own one stone and it is this one. A 3000 grit stone cannot set a bevel, so it needs a #1000 or coarser working alongside it to be of any use.
It is also overkill if you sharpen a single cheap knife now and then and never touch a Japanese blade.
5. Naniwa Chosera SS-400 Coarse Stone – The Repair Tool for Chips and Deep Damage
- Strong fast abrasive cut for bevel setting and chip repair
- Holds a hard edge so it resists dishing during coarse work
- Large working area suits wide bevels and reprofiling
- Cuts well on hard stainless and super steels
- Some users find it gentler than a 400 grit should be
- Absorbs water quickly and must be dried thoroughly
- Glued base stops even drying
This is the stone I reach for when a knife has been dropped, bumped in a drawer or left in a sink. A #400 grit face removes metal fast enough to erase a chip in a few controlled strokes, and the large 210 x 70 x 25 mm surface gives you room for wide bevels and reprofiling.
It is also the pick for very hard steel. On a thick SG2 or a German stainless blade, finer stones can stall, but the Chosera 400 keeps cutting and the surface does not clog with metal the way a soft stone does.
Splash-and-go again. Wet it, use it, wipe it. Like the rest of the Chosera line it comes with a toishi dressing stone, which is a useful little block for cleaning the face and knocking the slurry back to a flat working surface.
A minority of reviewers find it gentler than they expect for a 400 grit stone and would drop to something around 320 for really aggressive work. If you buy it for heavy reprofiling, buy it knowing it is a controlled repair stone rather than a metal removal machine.
The bonded base is the same compromise as the 3000. Convenient and stable, but it limits drying. Stand the stone up after every use and do not wrap it while it is still damp.
Is a 400 grit stone too coarse for daily use?
Yes. Used weekly it will grind your geometry down unevenly and thin the edge faster than you want, which is why it belongs on the shelf between repairs rather than in your regular rotation.
Reach for it when there is damage to remove, then move straight up to #1000 and finish as normal.
Can it fix a big chip in a nakiri?
Usually, if the chip is a shallow one along the edge. Straight bevel work on a nakiri at a consistent angle is straightforward, and this stone has the surface area to do it without constant reloading.
Deep chips that reach well into the blade, or a tip broken off, are closer to a restoration job than a kitchen sharpening session.
6. Naniwa Super Ceramic 1000 Grit Water Stone – Hard Steel and Hand Tools
1,000 Grit Super Ceramic Water Stone with a Base (Japan Import)
- Hard slow-wearing stone that holds its flatness
- Even cut with good tactile feedback
- Large surface suits chisels and plane irons
- Included dressing stone covers routine maintenance
- Costs more than entry level 1000 grit stones
- Bonded base prevents easy removal or flipping
- Must be dried after use
The Super Ceramic 1000 is a full-size Japanese water stone at 210 x 70 x 25 mm, bonded to a plastic base and shipped with a toishi. It is the same footprint and the same feel as a high-end Japanese shop stone, which is why it doubles as a tool stone.
When I sharpened a chisel and a plane iron on it, the difference was obvious. Those edges need square shoulders and a consistent length across the full width, and a wide flat surface makes that far easier than a narrow blade does.
On knives it cuts evenly and holds flat well. The feedback is smooth and continuous rather than gritty, and owners who compare it to cheaper stones consistently report noticing the difference.
The honest drawback is cost. It sits well above entry level, and if you sharpen nothing but a single kitchen knife the spend feels hard to justify against a simpler combo stone.
The bonded base is worth knowing about too. It is stable and it stops the stone walking, but it cannot be flipped, so you dry the whole unit standing up after use.
Is it worth more than a budget 1000 grit stone?
If you sharpen knives regularly, yes. The slow wear means fewer flattening sessions and a more consistent scratch pattern over the life of the stone.
If you sharpen a knife twice a year, no. Durability you never use is not a reason to spend more.
Can it handle VG-10 and SG2?
Yes. Both are hard steels that dull quickly, and a stone that keeps its flatness under pressure is exactly what you want. The surface is large enough to work the full bevel on a tall deba.
Pair it with the Chosera 3000 for a finish and you have a two-stone setup that covers almost everything a home kitchen throws at you.
7. KING Deluxe #1000 Medium Water Stone – The Best Stone for Learning by Feel
- True even 1000 grit with a uniform scratch pattern
- Hard and slow wearing for the money
- Excellent tactile feedback that teaches correct angle
- Thick stone that lasts a long time
- Cuts more slowly than newer stones of similar grit
- Dishes faster than premium ceramic stones
- No base or holder and no English instructions
The Deluxe 1000 is a single-sided, thick stone with no base and one job. It produces an even, true 1000 grit scratch pattern, and owners with large collections of stones regularly say it holds its own against Naniwa and Shapton options costing multiples of it.
What makes it valuable for beginners is the feedback. The stone is firm and slightly slow-cutting, so when your angle is wrong you feel the drag immediately instead of grinding metal away in silence. Several sessions on this stone and the muscle memory for a 15 degree bevel transfers straight to softer stones.
It is also thick enough to last. That matters if you want one stone that survives years of sharpening rather than one you replace when it dishes.
The trade-offs are honest ones. It cuts slower than modern stones of the same grit, so a dull knife takes more patience. And it dishes faster than premium ceramic, which means more regular flattening than the Shapton or the Chosera stones need.
There is no base in the package, and the instruction sheet is in Japanese. Expect to pick up technique from elsewhere the way most people do.
Is a slow-cutting stone good for a beginner?
Yes, and it is often better than a fast one. Slow cutting gives you time to correct your stroke before you have removed much metal, and the firm feel makes angle errors obvious.
Once you can hold an angle without thinking about it, speed starts to matter more and a faster stone pays off.
Why do owners flatten this one more often?
Because it is a slightly softer bond than the high-end ceramics, so the centre wears concave faster under concentrated pressure in the middle of the face.
A diamond flattening plate on wet newspaper every few sessions keeps it honest, and it takes two minutes.
8. Sharp Pebble 1000/6000 Whetstone Kit – The Budget Kit With a Built-In Angle Guide
Sharp Pebble Whetstone Knife Sharpener – 1000/6000 Grit Sharpening Stone
- Angle guide is praised by beginners for holding a consistent bevel
- Two grits cover most home kitchen sharpening
- Non-slip bamboo base keeps the stone steady
- Large review base shows consistent results
- A flattening plate is still needed eventually
- Freehand without the guide is hard for newcomers
- Small stone size is limited for long blades
The Sharp Pebble kit is a 1000 grit and 6000 grit water stone in a non-slip bamboo base with a fixed plastic angle guide, plus an instruction booklet. With more than 25,000 reviews behind it, it is the most proven kit on this list by sheer volume of use.
Owners consistently single out one thing: the angle guide. People who had abandoned sharpening entirely because they could not hold a consistent bevel come back with this kit and report bringing genuinely neglected knives back to cutting vegetables. It removes the one skill that stops most beginners.
The bamboo base solves the sliding problem that plagues stones without holders. You can push hard on the heel without the stone walking across the counter.
Experienced buyers raise a fair point: near-identical stones are sold by other sellers under different labels, so the value is in the base and the guide rather than in the stone itself.
Two more practical limits. The working surface is small enough that long blades and full-width chisel work is cramped, and you will still need a diamond flattening plate once the face starts to dish, which is a normal part of water stone ownership rather than a fault.
Is this a good first sharpening kit?
It is one of the few that solves the beginner problem out of the box. If you have never sharpened anything, the guide and the two-grit setup cover the whole basic cycle: sharpen, refine, strop.
Skill level decides the outcome more than the product does. Give it a few sessions and you will get an edge; expect it on the first try and you will be disappointed.
When should you move past this kit?
When you can hold a consistent angle without the guide and want a faster, harder stone with a larger surface. At that point a single quality #1000 plus a finisher beats another kit with a plastic attachment.
Also move on if you sharpen long blades regularly, since the working surface is small for that work.
How to Choose a Water Stone Without Overbuying
The biggest mistake in this category is buying a five-stone progression and using one side of it. One #1000 grit stone plus a flattening plate handles roughly nine out of ten kitchen sharpening jobs. Add a #3000 or #6000 grit finisher when you want the edge to look finished, and a #400 grit stone only when something is actually damaged.
What each grit number actually does
Grit numbers describe the size of the abrasive particles, and a higher number means finer particles. That is the whole meaning of the label, and everything else about a stone’s behaviour comes from how those particles are bonded and how hard the bond is.
Under #400 grit sits repair territory. This is where you remove chips, deep dullness and the damage that comes from cutting on bone or frozen food. Use it rarely and change to a finer stone immediately afterwards, because grinding away metal at a coarse grit is how edges get thin and geometry gets lost.
The #1000 grit range is where most knives live. It removes enough metal to fix a dull edge quickly and leaves a scratch pattern fine enough to refine easily. This is the single most useful number in the hobby.
Between #3000 and #6000 grit you are refining. The burr comes off, the edge stops looking like sandpaper, and the knife feels noticeably cleaner on a straight cut. Beyond that, #8000 grit and above add polish rather than cutting ability, which is why most people stop where the food stops noticing.
One caveat matters here. Grit labels are not standardised across Japanese makers, so a Shapton #1000 and a Naniwa #1000 do not feel identical. Feel under the knife is a more reliable guide than the number printed on the face.
Soaking stones versus splash-and-go stones
Traditional soaking stones sit in water for five to fifteen minutes until the water stops bubbling and the stone is saturated. The surface softens slightly, more abrasive is released, and the cut feels different and usually faster. Soaking stones are traditionally bound stones with a softer body.
Splash-and-go stones are vitrified ceramic. You wet the surface, work for a minute, add more water, and keep going. No preparation, and the stones are usually harder and stay flat longer.
The warning that matters: never long-soak a splash-and-go stone. Leave one submerged for hours and the uneven water absorption and expansion can crack it. Several owners of the Chosera stones report cracking, and bonded stones with a plastic base are the most vulnerable because one face dries before the other.
The habit that prevents most damage is simple. Stand the stone upright after every session and let both faces air dry fully before storing. Wiping it down is not enough.
How often should you flatten a water stone?
Every few sessions for normal home use, and after any heavy repair work. Hard ceramic stones ask less often, typically every six to eight sessions, while softer soaking stones may need it every two or three.
The test is cheap. Draw a pencil grid across the surface, sharpen the blade lengthwise a few strokes, and wipe away the graphite. Where the lines are erased you are cutting; where they survive the stone is high. A hollow in the centre is the usual pattern.
A diamond flattening plate is the standard tool. Laying it on wet newspaper or on a flat counter gives you a slightly abrasive surface that squares the stone back up in a couple of minutes. Sandpaper on a flat glass or granite plate works as a cheaper approach.
Matching the stone to your knife steel
Soft carbon steel sharpens quickly and easily on almost any stone, and it is the forgiving steel to learn on. Harder steels such as VG-10 and SG2 hold an edge longer but need a stone that stays flat and does not clog, which is where hard ceramic stones earn their place.
Very hard stainless and super steels may still need a diamond plate for the fastest material removal, but using one as a shortcut on a Japanese knife risks tearing the edge and ruining an asymmetric grind.
Single-bevel knives deserve their own note. The flat back stays flat and only the front bevel gets sharpened, so a dedicated coarse stone you can use at one angle without constantly changing your technique is more useful than a general purpose combo.
Why size and thickness matter
A larger stone gives you more working surface, which is why a 210 mm face suits long blades, chisels and wide bevels while a smaller blade suits a paring knife. Thickness matters separately, because a thin blade is cheaper and lighter but dishes faster and is more sensitive to any hollow.
Neither factor makes a bad stone. It makes a stone better or worse for a specific job, which is the whole basis of every pick in this guide.
For related sharpening and blade-care reading, our fixed blade hunting knife picks cover the edge geometry side of things, and if your knives live near salt water the corrosion angle matters as much as the grit does.
Frequently Asked Questions
How often should water stones be flattened?
Every few sessions for normal home use, and after any heavy repair work. Hard ceramic stones can go six to eight sessions between flattenings, while softer soaking stones often need it every two or three. Test with a pencil grid: draw the grid, run a few lengthwise strokes, wipe the graphite away, and any surviving lines mark a high spot. A diamond flattening plate on wet newspaper squares the face back up in a couple of minutes.
What is the best waterstone for sharpening knives?
The KING KW65 1000/6000 combination stone is the best starting answer because one box gives you a medium grit and a finishing grit on a stable base. The Shapton K0702 #1000 is the best single blade if you already have a finisher, and the Naniwa Chosera 3000 is the best finishing stone for a polished edge. For Japanese knives specifically, a #1000 grit water stone plus a flattening plate is a complete home setup.
Is 1000 grit okay for a Japanese knife?
Yes, #1000 grit is the standard working grit for Japanese knives and it is where most of the sharpening happens. It will not save you if the blade is badly chipped or very dull, because repair work needs #400 grit or coarser first. As the only stone you own it is fine for routine maintenance; as the first step on a neglected knife it will take a long time.
Is 1000 grit enough for knife sharpening?
One #1000 grit stone handles about nine out of ten kitchen sharpening jobs, including restoring a dull but undamaged edge. Add a #3000 or #6000 grit stone only if you care about how the edge looks and how it feels on a straight cut. Go coarser only when there is physical damage such as a chip or a deep dull spot, and always move back up to #1000 afterwards.
Which brand of sharpening stones is better, Naniwa or Shapton?
Naniwa stones are harder, cut smoothly with very good feedback, and polish to a higher gloss, which makes them the usual choice for VG-10 and SG2 steel. Shapton stones cut faster and stay flat longer, with less slurry and less loading, but they polish poorly at fine grits. Naniwa generally costs about twice as much as the equivalent Shapton model. Feel is a better decider than the grit number, since both brands label grit differently.
Do I need to soak Shapton Pro 1000?
No. Shapton stones are splash-and-go: wet the surface and start sharpening, adding water as you work. Never leave one submerged for long periods. A bonded splash-and-go stone that sits in water for hours absorbs water unevenly, and the resulting stress can crack it. Wipe it down and let it air dry standing upright after every session.
Final Verdict on the Best Water Stones for Japanese Knives in 2026
The best water stones for Japanese knives in 2026 come down to what your knives need from you. Buy the KING KW65 if you want one box to open and start, the Shapton K0702 if you want the fastest medium stone on the shelf, and add the Naniwa Chosera 3000 when you want an edge that looks finished. Keep a coarse stone like the Naniwa SS-400 on hand for chips, and whatever you choose, flatten it and dry it properly.
Whatever you pick, add a diamond flattening plate to your order before you add another grit. A true water stone gives you a thin edge you can maintain for years, and only a flat surface will keep it. For knife types that see salt water and bone as often as food, our dive knife safety picks cover the corrosion side of that maintenance picture.