Question 1

What is ITTENDO?

Accepted Answer

ITTENDO is a Japanese numismatic archive. We collect auction records, classifications, and sources for Japanese coinage, and publish them in a form anyone can verify — including how each figure was calculated and what we excluded.

Question 2

Is the service free to use?

Accepted Answer

Core features — articles, price guides, glossary, etc. — are free. Certain premium features (detailed analysis reports, etc.) are planned to become paid offerings in the future.

Question 3

Can I use ITTENDO without registering?

Accepted Answer

Yes. Browsing articles and checking price guides requires no account. Free registration is required to use Watchlist, Vault (collection management), and notification features.

Question 4

Where does ITTENDO's auction data come from?

Accepted Answer

We collect transaction results from major domestic auction houses. Data is updated on a regular basis.

Question 5

How reliable are the price guides?

Accepted Answer

Price guides are based on actual auction transaction data, but they are reference values only. Individual prices can vary significantly depending on condition and lot composition.

Question 6

What is Watchlist?

Accepted Answer

Watchlist lets you register antique coin categories or specific types you are interested in. You will receive notifications when preset conditions are met — such as a target price, a percentage drop, or a new auction record.

Question 7

What is Vault?

Accepted Answer

Vault is a personal collection management feature. You can record purchase prices, grades, notes, and other details about your coins to track and understand your collection's value.

Question 8

How do I request an appraisal for sale or consignment?

Accepted Answer

Simply upload photos through our appraisal form. Please take clear shots of the obverse, reverse, and edge of your coin. Our team will contact you shortly after submission.

Question 9

Is the appraisal service free?

Accepted Answer

Photo appraisals are free of charge. In-person appraisals requiring you to mail the coin are also generally free, though return shipping costs may apply.

Question 10

What is a typical buyback price?

Accepted Answer

Buyback prices are typically 60–80% of the current auction market value. They vary based on condition, rarity, and demand. We recommend checking the ITTENDO price guide for your coin before submitting a request.

Question 11

How can I spot counterfeit or altered coins?

Accepted Answer

Our Counterfeit & Altered Coin Alerts page lists known techniques and detection tips by category. Key indicators include weight, depth of character engraving, and casting texture. When in doubt, consult a professional grader.

Question 12

What is a coin grade?

Accepted Answer

A grade reflects a coin's state of preservation. Common grades include Mint State (MS), About Uncirculated (AU), Extremely Fine (EF/XF), and Very Fine (VF) and below. The same type can command prices several times higher in top grade.

Question 13

Can I request authentication through ITTENDO?

Accepted Answer

ITTENDO is not itself an authentication service, but we can refer you to reputable graders and JNDA-member dealers. Please contact us via the inquiry form.

Question 14

How should I store antique coins?

Accepted Answer

Keep coins in a stable temperature and humidity environment, away from direct sunlight, high humidity, and sulfur-containing materials (rubber bands, etc.). Use dedicated coin holders or capsules, and always handle coins by their edges.

Question 15

My copper coin has turned green. Is that a problem?

Accepted Answer

Green patina (verdigris) is natural oxidation. Stable patina generally does not harm value. However, if it is powdery and spreading, improve storage conditions immediately. Never abrasively clean the coin.

Question 16

Can I clean my coins?

Accepted Answer

As a rule, no. Polishing or chemical cleaning significantly lowers grade and can destroy original surfaces. Original casting texture (patina) is often highly valued by collectors and graders.

Question 17

What determines the value of an antique coin?

Accepted Answer

The main factors are rarity (mintage and surviving population), condition (grade), demand (popularity and trends), and auction transaction history. Even within the same type, varieties (script style, mint mark) can cause significant price differences.

Question 18

How is the antique coin market trending lately?

Accepted Answer

Check the News section and Heatmap on ITTENDO for the latest movements. In recent years, growing demand from overseas buyers (particularly China and Taiwan) has pushed up prices for Kan'ei Tsūhō and early modern silver coins.

Question 19

When is the best time to buy or sell?

Accepted Answer

Market activity peaks in spring (April–May) and autumn (October–November) when major auctions concentrate. Use the Watchlist to set a target price and receive an alert when conditions are right.

Question 20

How do I get started collecting Japanese antique coins?

Accepted Answer

We recommend beginning with Kan'ei Tsūhō (Mon coins), which are affordable and widely available. Build foundational knowledge through Coinpedia articles, then make small purchases from reputable dealers or auctions.

Question 21

There are so many types — where should I start learning?

Accepted Answer

Browse Coinpedia by category (era, type) and choose a period that interests you. Each article explains classification, varieties, and known fakes. You can also use the search function to look up a specific coin name.

Question 22

Can antique coins be a genuine investment?

Accepted Answer

Rare coins have seen multi-fold price increases over the past 10–20 years, but liquidity is lower than equities and selling takes time. It is best to start by enjoying the hobby and building knowledge before treating coins as an asset class.

Question 23

What was Japan's first official currency?

Accepted Answer

Wadō Kaichin, minted in 708 (Wadō 1), is generally recognized as Japan's first official coin. Some researchers argue that Fuhonsen (c. 683) preceded it — the debate continues among historians.

Question 24

Why was Kan'ei Tsūhō the most widely circulated coin in Japan?

Accepted Answer

Kan'ei Tsūhō was minted continuously for over 250 years from 1636, produced in large quantities at mints across the country. Hundreds of varieties exist based on script style, mint, and material, making it one of the most popular series for collectors at every level.

Question 25

What was the Edo-period three-currency system?

Accepted Answer

Gold, silver, and copper coins circulated simultaneously. Gold coins (koban, ichibukin, etc.) were used for large transactions; silver coins (chōgin, mameitagin, etc.) traded by weight; copper coins handled everyday small purchases. Exchange rates fluctuated, making money changers (ryōgaeya) a crucial part of the economy.

Question 26

How do I get my dealership listed?

Accepted Answer

Please contact us via the inquiry form and let us know you would like to be listed. We will review eligibility — including JNDA membership and other credibility criteria — before proceeding.

Frequently Asked Questions