What Microscopy Shows After Stropping VG10 and SG2 Kitchen Knives

Plain-language summary: Tokushu Knife requested third-party microscopy images of used VG10 and SG2 kitchen-knife edges before and after stropping with Tokushu Knife Strop Shots. In the photographed areas, the used edges show more visible irregularity, while the images taken after the 2 micron stage show a cleaner, more continuous-looking apex and a changed scratch pattern. That appearance is consistent with abrasive edge refinement. It is not, by itself, a measurement of sharpness, bite, cutting force, or edge retention.

Commercial disclosure: Tokushu Knife sells the stropping compound discussed here and supplied it for this informal comparison. The microscopy was performed outside Tokushu Knife, but this was not an accredited laboratory study, a standardized sharpness test, or peer-reviewed research. We are publishing the useful observations and the limitations together so readers can judge the evidence for themselves.

Why we are publishing the images

Most stropping advice asks customers to accept claims such as “realigns the edge,” “restores sharpness,” or “finer is always better” without showing what happened at the apex. These images give us a closer look at representative VG10 and SG2 edges through successive maintenance stages.

The honest conclusion is narrower than a typical marketing claim: the sampled edges look visibly different after stropping with the 2 micron abrasive. The images help explain the surface change, but functional performance still has to be judged by cutting behavior or a standardized sharpness test.

Case study at a glance

• Internal reference: TK-EDGE-CASE-01
• Steels shown: VG10 and SG2/MC63 kitchen-knife edges
• Primary treatment: Tokushu Knife Strop Shots 2 micron polycrystalline abrasive on a leather strop
• Sequence: The same edge was followed through the successive stages unless a figure label says otherwise. The photographed field was not registered as the exact same microscopic location at every stage.
• Views supplied: 11.2×, 56×, and 179×, with scale bars printed in the figures
• Testing format: Informal third-party microscopy requested by Tokushu Knife
• Not recorded in a formal protocol: Microscope model, edge angle, compound quantity, leather firmness, pressure, pass count, cleaning method, repeat samples, and statistical analysis

How to read these images

The lowest row gives the closest supplied view of the apex. Look at the continuity and regularity of the line where the two bevels meet, as well as the scratch pattern immediately behind it. Do not treat the apparent thickness of the bright line as a measured edge radius: lighting, focus, orientation, and the exact photographed location can all change its appearance.

The final “0.5–1 micron” stage in the supplied composites followed the 2 micron stage on the same edge. It is therefore a sequential finishing stage, not an independent head-to-head control. Because its label groups more than one micron value, we are not using that column to claim that one specific fine compound outperformed 2 micron.

SG2/MC63 observations

What is visible

• The sampled used edge has a visibly less regular apex at the closest supplied view.
• After the 2 micron stage, the photographed apex appears more continuous and even.
• The surface scratch pattern behind the apex changes after stropping, showing that the abrasive contacted and altered the tested edge surface.

What we infer—and what we do not

The visual change is consistent with the 2 micron polycrystalline abrasive refining the sampled edge. The image does not quantify how much sharper the knife became, whether its edge retention improved, or whether another compound would produce better cutting performance.

VG10 observations

What is visible

• The sampled used VG10 edge shows a visibly uneven, worn-looking apex in the closest supplied view.
• After the 2 micron stage, the photographed apex looks cleaner and more continuous.
• The bevel immediately behind the apex shows a different, more uniform-looking scratch pattern after treatment.

What we infer—and what we do not

As with the SG2 example, the appearance is consistent with abrasive refinement of this tested edge. It is not evidence that every VG10 knife will respond identically, and it does not show that stropping can repair a chip or replace stone sharpening.

What this microscopy does not prove

• It does not provide a numerical sharpness score or cutting-force measurement.
• It does not measure edge retention after repeated cutting.
• It does not establish that Tokushu Strop Shots outperform another brand.
• It does not isolate 2 micron and the subsequent finer stage as independent treatments.
• It does not prove burr removal from every viewing angle.
• It does not generalize from these representative edges to every heat treatment, geometry, steel, strop, or user technique.

This distinction matters. CATRA’s knife-edge equipment measures sharpness and durability through controlled cutting tests conforming to BS EN ISO 8442-5. A microscope can document visible edge condition, but a functional performance claim needs a functional test.

Why Tokushu recommends 2 micron for kitchen knives

Our practical recommendation is based on sharpening and kitchen use, not on pretending that a photograph can measure “bite.” For most Japanese kitchen knives, 2 micron is our default finishing and touch-up compound because it refreshes a useful, toothy working edge. That is the kind of edge many cooks want for tomato skins, peppers, proteins, and everyday prep.

• 2 micron Strop Shots: Tokushu’s default kitchen-knife recommendation when useful bite is the goal.
• 1 micron: Also appropriate for kitchen knives when a somewhat finer finish is preferred.
• Below 1 micron: Primarily for straight razors, specialized finishing, or users intentionally pursuing a mirror-polished bevel. Finer is not automatically better for food preparation.

Do not move through every available micron simply because it is possible. Choose the finish for the way the knife will actually be used.

How to strop without rounding the apex

1. Use a stable, firm, flat strop surface.
2. Apply a light, even layer of compound. More compound is not necessarily better.
3. Use edge-trailing strokes, moving the spine ahead of the cutting edge. Never drive the edge forward into the leather.
4. Keep a consistent angle and use light pressure.
5. For a standard double-bevel knife, alternate sides and check the edge frequently.
6. Stop when the desired bite returns, then wipe the blade completely clean before food preparation.

There is no universal pass count. Steel, edge condition, angle, pressure, leather firmness, and abrasive all affect the result. Excess pressure, an angle that is too high, or unnecessary stropping can round the apex and make the knife feel less sharp.

When stropping is not enough

A leather strop maintains and refines an existing edge. Use whetstones or professional sharpening when a knife is chipped, heavily dull, has uneven bevels, or does not improve after brief, careful stropping. The chip-repair sequence supplied with this project shows the visible damage disappearing during the stone stages—not because of the strop.

Browse our leather strops and compounds, or contact the Tokushu sharpening team if you are unsure which maintenance step your knife needs.

Frequently asked questions

Does the microscopy prove the knives became sharper?

No. It shows a visible difference in the sampled edge surfaces. A claim about sharpness requires a cutting or force measurement under a defined protocol.

Was this an independent laboratory test?

No. Tokushu Knife requested and supplied the compound for an informal third-party microscopy comparison. It was not an accredited, standardized, or peer-reviewed laboratory study.

Why show the results if the test was informal?

Because the images are useful when their scope is stated accurately. Publishing the commercial relationship, available method, original scale bars, and limitations gives customers more information than an unsupported performance claim.

Can 2 micron compound repair a chipped knife?

No. Chips and major dullness require abrasive removal and edge reconstruction on stones or through professional sharpening.

Why not recommend 0.5 or 0.25 micron to every kitchen-knife owner?

Those finer compounds emphasize polish. For normal kitchen work, a highly polished edge is not automatically more useful than the practical bite produced by 2 micron, while 1 micron remains a good finer kitchen option.

Related technical references

• John D. Verhoeven, Experiments on Knife Sharpening, 2004. This technical report used scanning electron microscopy to examine sharpening methods, leather stropping, burrs, and diamond polishing compounds. It provides useful context; it did not test Tokushu Strop Shots.
• CATRA, Automatic Edge Tester. CATRA explains how controlled cutting tests measure initial sharpness and edge durability under BS EN ISO 8442-5.
• McGorry, Dowd, and Dempsey, A technique for field measurement of knife sharpness, Applied Ergonomics, 2005. The study relates measured cutting force to changes in blade sharpness.

What we will test next

A stronger follow-up should record the knife and hardness, starting edge condition, angle, strop surface, compound mass, pressure, pass count, cleaning procedure, and the same registered imaging locations. It should include multiple samples plus standardized sharpness measurements before and after stropping, followed by an edge-retention test. If we conduct that work, we will add it here and preserve this page’s revision history rather than rewriting the original limitations.

Revision status: Initial case-study draft. Image files, publication date, and future corrections will be logged on this page.