Unusual Japanese cash id [solved]

It is around 20mm and weighs around 1.459g

In addition to the reply from Reslumi in your post http://en.numista.com/forum/topic164303.html I offer the following:

There are listed in the books by Hartill (4.218 and 4.219), Jones (288 and 289) and Ogawa (309 and 310) [see below], coins with your inscription and plain reverse, as well as the unusual small diameter and large center hole, that are attributed to the Kuzumaki casting site in Rikuchu Province that were issued by the Hachinohe clan for circulation only within their domain.  Hartill states these coins to be rather common and that they were cast from 1865 to 1867 (Jones and Ogawa state the casting period to be unknown).  Because the first character (on the right in your posted image) 寛 nearly lacks the legs at the bottom, it is consistent with the latter images in all three texts (to be fair, Jones had permission to use the Ogawa rubbings).  However, all three texts state the circulation coins were cast in iron and thus would respond strongly to a magnet.  At least your coin looks in the image to be copper or a copper alloy.

If not magnetic, there remains the more remote chance you have a bosen, a coin used to manufacture the iron coins.  Only Ogawa mentions a “rarity index” for the bosen, giving them a score of “6” (a score of “10” being the most common).  The iron circulation coins are given a score of “7”.  Hmmmm.  Recalling that Hartill considered the circulation coins to be “common”, we might infer that the bosen are not that difficult to encounter.  A sharpness to the inscription is normally expected in bosen.  I am not an expert, but your image does not look at first glance to be of bosen quality.  However, Hartill describes these as “small poor coins” and Jones as “very small flan, crude”, so perhaps the bosen had a similar lack of quality.  Another person may be a better judge, but you can consider the possibilities yourself.

Even if (and I do say if) the Hachinohe clan lacked permission of the ruling authority to cast these coins, collectors of Japanese cash coins still consider these to be of interest.

David Hartill, Early Japanese Coins, A Bright Pen Book, 2011

Robert M. Jones, History and Guide to the Copper Cash Coinage of Japan, Morris Publishing, 2007

Yoshinori Ogawa, Shin Kan'ei Sen Kanshiki To Tebiki, Bankoku Kahei Kenkyukai, 1969

Thank you for the information, however a question still remains. How can we differenciate between where the immitations were made as https://www.zeno.ru/showgallery.php?cat=15449 in the link the immitations shown all seem to be a coin with the same obverse and reverse the coins similar to mine all seem to be the same?

Sorry, but I can not help you more.

For me, it is sufficient to make a match to a coin in the reference books I mentioned.  

Whether a casting site was approved by the Shogunate or not approved is only an additional detail (it does not impact merit to be part of a coin collection but rather provides more details about the specific coin).  Also, the approval status depends on each expert's interpretation and can change as new information is uncovered by researchers.

Perhaps others can provide more information.