Case studies
A Japanese pre-owned watch retailer, measured — and how the same shape applies in other industries.
Measured: a pre-owned watch retailer
The company is not named. It is a Japanese retailer of pre-owned luxury watches. Every figure below was measured; none was invented for illustration.
Where they started
They knew their own inventory. Cost, listing price, days on hand — all of it sat in their own systems. What did not sit anywhere was where that inventory stood in the world this morning.
They knew foreign buyers were purchasing through parallel channels, and that walk-in customers at the Japanese stores were often visitors. So a price gap existed. Which references carried the gap, and how large it was, is published by nobody.
What was measured
Twelve model families, read every morning across 50 sources in Japan and overseas. Every row records the seller, the listing URL, the moment it was read, and the exchange rate applied, along with the date that rate was published.
| Measurement | Value |
|---|---|
| References matched across markets | 44 |
| Inventory reconciled (ex-tax) | 777 items / ¥2,036,585,182 |
| Japan → United States, median gap | +9.2% |
| Japan → Hong Kong, after tax normalisation | −4.3%, with 4 references *dearer* in Hong Kong |
| Export candidates in the high-confidence band | 156 items / ¥55,749,833 |
What was lined up to produce these numbers
Taxes aligned before comparing
Hong Kong levies no consumption tax; the Japanese listing price includes 10%. Every source declared its tax treatment, the ex-tax price was resolved once at collection, and comparisons read only that column.
On that basis the Hong Kong gap is −4.3%, and 4 of 16 references are dearer in Hong Kong. The references that should not be exported can be set aside first.
A general-purpose assistant gives a different answer
On 20 August 2026 we asked a chat assistant what a given reference cost in Japan and the United States. It reported the two markets as roughly level. Measured the same day on a like-for-like basis, the American market was 17% above the Japanese one.
Both of the assistant's figures were correct. One was a trade-in price and the other a market index, and nothing in the answer distinguished them. The sign of the difference flips, and the pricing of an entire inventory turns with it.
Absence confirmed twice
A listing leaving a results page is the closest public proxy for a sale. A disappearance is counted only after two consecutive absences, and the count resets the moment a listing reappears. A listing that merely moved down the page is not counted as sold.
Thirty-one checks before anything is published
The case-study figures are published only after passing 31 checks — whether accessories are being counted as watches, whether a reference suffix has been dropped, and so on.
What transfers
Any category with model numbers, the same item listed across several venues, and prices that differ by country fits the same shape. The only part specific to watches is the list of sources.
Industries where this shape fits
Wherever the same item appears on several sales pages under a code or a name, and the price differs by country or channel, it works the same way.
- Consumer electronics and PC accessories — which seller lists the same model, at what price, per marketplace
- Cosmetics and supplements — listings by sellers not on your authorised list, with their price and country
- Automotive parts and industrial supplies (B2B) — sellers and listed prices in distributors' public catalogues, at home and abroad
- Food and drink going overseas — prices on sales pages in the target market, read every morning over that country's connection
Beyond these: if the same item appears on several surfaces under a code or a name, and the price differs by country or channel, the shape carries over unchanged. Get in touch to try it on your own catalogue.
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