How Accurate is the Attribution of Kanei Tsuho?

The following question came from David.

“Do you know how the Japanese arrive at mint attributions for Kanei without obvious mint marks on the back? Is there a vast collection of samples submitted by the mints that has been retained or something?”
David’s question is a good one! I cannot speak for Ko-Kanei (古寛永) coins, as I know very little about them. However, having fooled around with Shin-Kanei (新寛永) coins more frequently, I believe I can answer his question, or I can at least pretend to know and come up with plausible statements.

Let us first begin by using the process of elimination and take away those coins with mintmarks. They represent about a third of the total population. In addition, many of those mintmarked varieties have brothers and sisters in which all of the obverse characters are written the same but lacking only the reverse mintmarks. They account for nearly 15% of the total population. Thus, so far, we were able to discount almost half of the varieties.

Some varieties are attributed to certain mints because there are similarities with the known varieties. For such coins, Japanese use the term “DE” (手) as a suffix. Koume-De (小梅手) is a good example. It simply means this particular variety contains certain elements associated with those coins made at Koume mint. Because the color of copper used is also taken into account, such attribution may be accurate. On the other hand, some varieties are called “DE” (手) simply to suggest “in the manner of.” Perhaps, such coins account for about 5% of the total population.

For those varieties that are not possible to attribute, they are classified as “unknown mints,” which represents about 5% of the population. The Japanese term is “FU-MEI” (不明), but this term differs between Japanese attribution guides. A few authors have attempted to place such coins into one of the known mints, while taking away others and placing them into the “unknown mint” category.

Because many Japanese numismatic works have been published in the 1700s and the 1800s, contemporary to the casting of many of the coins, and that there existed many collectors as well during that time, much of what was published is regarded as being quite accurate. Any collector of means with ties to mint operators could have easily obtained seed coins. Such dealings were not out of norm. In the 19th century coin collectors in the United States were also able to obtain many rare items such as proof coins, patterns, and even “special” unique coins that were made especially for certain collectors.

In the 20th century, archaeological digs in Japan have uncovered many mint operations. When remnants of molds and coins are found, attribution does become science.

David asks a very good question about submission of samples. There are records of permission for making money. However, there existed many more unauthorized mints than those permitted by the central government. We have to remember that Japanese provinces operated individually. For the most part, attribution of Kanei Tsuho can be trusted.