This series is obscure. Between the obscurity and origins in a country with a language so unfamiliar to most English speakers, it's a challenge to figure out what's going on. In fact, to even get your feet in the water, there are a few things we need to understand. Let's get those out of the way.
You can also find a short video intro from my appearance on The Coin Show in March 2021, though it isn't as thorough as that below.
Ryo - The highest denomination in pre-Meiji Japan
Bu - 1/4 ryo
Shu - 1/4 bu. In the 1850s, one shu was equal to a day's pay for a construction worker.
Mon - A copper denomination that isn't critical to understanding bar money
For bar money, we'll only be looking at bu and shu. These came in the amounts of one and two (ie. there are bars worth one bu and bars worth two bu).
Ichi - Japanese for one
Ni - Japanese for two
Note that in Japanese, the letter "i" always makes the "ee" sound. Ichi is not pronounced "itchy," but rather "ee-chi."
It's common practice in Japanese to combine words in certain situations. As a result, we end up with...
Isshu - Ichi shu - One shu
Nisshu - Ni shu - Two shu
Ichibu - Ichi bu - One bu
Nibu - Ni bu - Two bu
Finally, most types of bar money are sometimes seen with an additional word at the end noting whether it's gold or silver. I've omitted this on the Gold Set and Silver Set pages because they're already separated by metal, but you may see it elsewhere or in the Research Notes.
Gin - Silver
Kin - Gold
(Remember the sound "i" makes; these are pronounced "geen" and "keen.")
If you have a silver coin worth one shu, that would commonly be written "isshu gin."
Also note that Japanese is read top to bottom, right to left. This is helpful to remember when looking at legends, particularly on the silver Nanryo pieces.
To talk about how bar money is named and dated, we need a quick intro to the Japanese government system. The overarching period that includes bar money is known as the Edo period (pronounced "ay-doe," not "ee-doe"), also sometimes called "pre-Meiji," which lasted from 1603 to 1868. However, the Edo period is broken up into smaller eras.
During the Edo period, Japan technically had an emperor, although he had very little power. The person actually in control of the country was the shogun, a position passed down hereditarily through the Tokugawa family starting with Tokugawa Ieyasu at the start of the period.
While the emperor couldn't do much, the era name changed every time the throne changed hands. For example, the Ansei era began in late 1854 when emperor Komei-tenno took the throne and ended in early 1860.
Japanese bar money does not have a date printed on it. However, they are named based on the era when the design was first minted. The type of silver ichibu first minted in 1859 is known as Ansei ichibu gin because they began during the Ansei era.
Designs didn't necessarily change when a new era began. The Ansei ichibu gin were produced with the same design and composition through 1868, well after the Ansei era had ended.
In addition, not all pieces named for the same era were struck during the same dates. The Ansei nibu was struck from 1856-1860, and the Ansei ichibu kin was only struck in 1859. All are named Ansei because they began within that era, but all have different ranges.
There are eras where new things tended to be minted. You'll see a lot of pieces named for the Ansei era, but only one for the Kaei era. In an extreme case, the only piece of bar money minted from 1601 until 1695 was the Keicho ichibu kin. Every era inbetween was skipped over with no new types. There was usually a historical impetus for the issuing of new pieces, but we'll discuss those in more detail over on the set pages (eventually).
In summary, in order to date a piece, all you need to do is identify the type (which is sometimes easier said than done). That will give you a date range, and that's as close as we can get.
Currently, the only US companies I'm aware of that grade bar money are PCGS and ANACS. NGC does not accept any pre-Meiji Japanese coinage. The sets on this site reference PCGS frequently and use their population numbers. ANACS is not included in this because their grading criteria for this series appear to be wildly different than PCGS's, and it would be unfair to group them together. Regardless, I believe there are only a handful in ANACS holders.
Overall, a very small percentage of these pieces have been graded. They trade hands most often within Japan, and they aren't nearly as dependent on third party grading as the US is. In fact, the six most commonly graded types make up roughly 3/4 of the total graded populations; these are the same six that are most easily found for sale in the US. This is not a comment on rarity, but rather on how often they trade hands in the states.
For the most part everything is explained in context, with one exception: ID numbers. The US can't seem to decide what numbering system to use to refer to bar money, so I've included quite a few.
First is the PCGS number. This is arguably the most useful. You can copy this straight into CoinFacts to view the population data yourself. It's also useful if you're submitting pieces for grading and need the number for your submission form.
Next is the Craig or Friedburg number, depending on the piece. Krause uses the numbers first put forth in Coins of the World, 1750-1850 by William Craig, but uses the numbers from Gold Coins of the World, originally by Robert Friedburg, for the pieces not covered in Craig. Since these numbers were used in Krause, they're referenced most frequently by people unfamiliar with the series.
Third is the Hartill number. Early Japanese Coins by David Hartill is by far the best English reference, and he established his own numbering system within that book. Those numbers haven't seen wide use anywhere else as far as I'm aware, but they're useful for anyone with the book in hand.
Finally we have the JNDA number. The JNDA is a yearly catalogue issued by the Japanese Numismatic Dealers Association that is essentially their equivalent of the Redbook. It's in Japanese, but PCGS includes these numbers on all current holders (sometimes in addition to the Craig numbers).
I've included mintages on the set pages. You'll quickly notice that there are some massive mintages up into the hundreds of millions, but don't let the numbers fool you; the purpose of new designs was to melt down the old pieces and make the new ones, usually debasing them for a profit. This was especially the case for gold coins (although most of their mintages were recorded together with koban and are therefore unknown), but silver pieces like the Ko Nanryo and Tenpo ichibu gin were also particularly susceptible to melting. The surviving numbers are much, much lower than the original mintages. Unfortunately, since so few have been graded, we don't have a good estimate of what those survival rates are.
No one can seem to agree on which side is the obverse for a lot of issues. For simplicity's sake, I've chosen to refer to whichever side is shown first on the corresponding PCGS TrueView as the obverse, regardless of whether or not I agree. I'll discuss this in more detail in the eventual book.
The standard for all types of bar money is medal aligned. Most pieces can occasionally be found in coin alignment, and these examples are worth more. PCGS will grade them as errors. They bring quite a premium in Japan and are listed separately in the JNDA, but I haven't seen enough sale records in the US to comment on whether they have a similar value jump here.