Testing Methodology
Testing Methodology
This page describes how we test knives when we test them, and which tier of testing each score comes from. Ranking articles built from published specifications rather than hands-on use say so at the top of the article. Publishing our test conditions in detail lets readers see exactly how our scores are produced.
01How we acquire knives
Knives we test are bought at retail, with the editorial team's own budget, as ordinary customers. We do not accept samples from manufacturers or retailers.
Why we buy at retail
Samples can be hand-picked or specially prepared by a manufacturer. Buying at retail means we evaluate the same knife an ordinary buyer would receive. For the Kappabashi $150 field test, one knife was bought from each of six shops on the same day.
02Two tiers of testing
We run two kinds of test, and every score on the site is labelled with the tier it came from. A single-session comparison and a month of daily use answer different questions, so we never present one as the other.
Tier A — Single-session cutting comparison
- • Knives bought at retail on the same day and tested with the factory edge as sold.
- • Same ingredients, same cutting board, same person, one session.
- • One pass per knife per ingredient; knives ranked 6 → 1 points per ingredient; every cut photographed.
- • Measures: how the edge feels going in, the cut surface, and how the food releases.
- • Does not measure: edge retention, ease of sharpening, or durability.
- • Published: the Kappabashi $150 field test (April 2026, six shops, three ingredients) and the Kappabashi sharpening comparison.
Tier B — Long-term use test
- • At least four weeks of use, with observations recorded weekly.
- • The full six-ingredient rubric below, plus a 30-minute continuous-use session.
- • Sharpening on #1000 and #6000 whetstones; recovery and ease of resharpening assessed.
- • Status: as of September 2026, no knife on this site has completed a Tier B test.
- • When one does, the article will carry a Tier B label and the test dates.
03Cutting rubric — six ingredients for Tier B; Tier A uses three of them (tomato, onion, daikon)
We use a fixed set of ingredients and tasks so knives can be compared on equal terms. The full six-ingredient rubric is the Tier B protocol. The Tier A field test used the first three: tomato, onion, and daikon.
| Food | What we measure |
|---|---|
| Ripe tomato | Skin bite, thinnest clean slice possible |
| Onion (medium) | Food release on thin slices, clean cut through cell layers |
| Daikon (10 cm round) | Katsuramuki rotary peel possible, resistance on push cut |
| White fish (sea bream / sea bass) | Skin removal, hira-zukuri slice, pull cut smoothness |
| Herbs (parsley, shiso) | Damage at the cut surface, aroma retention |
| Chicken thigh | Tendon handling, work around bone |
In Tier B, a 30-minute continuous-use session additionally tracks grip fatigue and how quickly the edge dulls.
04Scoring
For each test category, the six knives in a ranking session are ordered from 1st to 6th. 1st place earns 6 points, 2nd place 5 points, down to 1 point for 6th. No fractional or decimal scores are used.
Final ranking is the total across all categories. Ties are broken by the tester's overall judgment (balance, feel in hand, price-to-performance). Scores are fixed on the day of the test and are not revised afterwards.
05Hardware specs measured
HRC (Rockwell hardness)
Brand-disclosed values. We do not run our own destructive testing.
Edge angle
Visual inspection plus tape-angle measurement. Margin of error ±1°.
Weight
Digital scale, ±1g.
Blade length
Stainless ruler, ±1 mm.
Price
Taken from the purchase receipt, at the time of testing, tax-inclusive when bought in Japan. If we have no receipt, we do not estimate — the article says "price not recorded".
Steel
Manufacturer disclosure. Labeled "undisclosed" when the brand does not publish the steel type.
06Standardized conditions
To isolate the difference between knives, we hold every other variable constant.
- • Cutting board: The same board for every knife within a session.
- • Tester: The same person performs every cut within a session.
- • Photography: Same camera position for every knife.
- • Edge: As sold, with no sharpening before the test.
- • Ingredients: Bought from the same shop on the same day.
07Excluded from scoring
Certain qualities are never part of our point totals. We may comment on them in the article body, but they do not affect ranking.
- • Aesthetic appearance and decorative finishing
- • Brand prestige or history
- • Packaging quality (wooden boxes, gift presentation)
- • Suitability as a gift item
These are valuable considerations but depend on subjective preference, so they don't belong in an objective ranking.