Japan - Genroku Cho Gin Verification

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Author	Replies: 7 / Views: 1,701
Miguel_85 New Member Poland 13 Posts	Posted 10/24/2023 05:46 am Hello :) Could someone help with verifying if this bar is genuine? I've made some research and I assume that this is Cho Gin from Genroku period - year 1706, all stamps looks like on other bars from this period. I have some doubts though as my bar is lighter (74 grams - 76mm x 28mm) than other ones found online (most between 120-150 grams). On the other hand I read that these bars were used for trade purposes only and in most cases were put in a sealed paper bag called Hogin with other Cho Gins and Mameita Gin to make all transactions easier. So, maybe some of Cho Gins had to be made lighter in order to make the correct Hogin weight? Report this Post to the Staff

Spence Moderator United States 34410 Posts	Posted 10/24/2023 6:55 pm @mig, it might be hard to know for sure as it would seem somewhat easy to imitate with modern counterfeiting technology. Here is what I would do if this was mine, in increasing order of difficulty and cost: 1. Evaluate the provenance. Who owned it last and has it ever come up for sale before (e.g. on acsearch). 2. Measure the specific gravity. 3. Measure the silver content. 4. Measure trace elements. The first two should be relatively easy and just take a little effort on your part, whereas the second two rely on technology to which it may not be easy for you to gain access. "If you climb a good tree, you get a push." -----Ghanaian proverb "The danger we all now face is distinguishing between what is authentic and what is performed." -----King Adz Report this Post to the Staff
gxseries Pillar of the Community Australia 3831 Posts	Posted 10/25/2023 05:45 am More information here: https://www.japanesewiki.com/histor...0coins).html I think the biggest problem that I have is that the wear is very inconsistent with the front and reverse. This is supposedly cast 300 years ago and used in trade for about 150+ years. It doesn't add up. I vote for a replica. My partial coin collection http://www.omnicoin.com/collection/gxseries My numismatics articles and collection: http://www.gxseries.com/numis/numis_index.htm Regularly updated at least once a month. Report this Post to the Staff
Miguel_85 New Member Poland 13 Posts	Posted 10/25/2023 06:03 am Thanks @Spence, well this was bought online from Antics Store described as: Cho Gin Silver Bar Km 55, silver/ copper 60/40 %. I've tried specific gravity test. So, dry weight is 74g. I put a container with very cold water inside and zeroed the scales. Weight of this bar when suspended in water is 9.90-10g. So I divided 74g / 9.95-10g so result is around 7.4 What does it mean? Thanks @gxseries - I've found this page some time ago. Nice peace of knowledge. Edited by Miguel_85 10/25/2023 07:30 am Report this Post to the Staff
Sap Moderator Australia 16829 Posts	Posted 10/25/2023 7:04 pm Quote: So I divided 74g / 9.95-10g so result is around 7.4 What does it mean? It means it's not silver. The theoretical specific gravity of a 60% silver, 40% copper alloy is somewhere around 9.8. A specific gravity of 7.4 implies some kind of lightweight brass, probably aluminium-bronze. Or maybe it's mostly made of tin. It also means the other examples you spotted, with weights over 100g, probably are silver (assuming they're about the same size). A second strike against it, for me, is the stamps. Inside the stamps, the surface is all bubbly with raised dimples, as if it were cast. The genuine ingots themselves were cast, but the stamps should have been literally stamped onto the ingot after it was cast. Signs of casting inside the stamps means the entire ingot must have been cast, and is therefore fake. Whether it's a modern fake or a contemporary one (circulating counterfeit), would be the next question. Don't say "infinitely" when you mean "very"; otherwise, you'll have no word left when you want to talk about something really infinite. - C. S. Lewis Report this Post to the Staff
Miguel_85 New Member Poland 13 Posts	Posted 10/27/2023 06:30 am Yesterday I went to very reliable numismatics store (however they do not specialize in Far East coins) and asked for opinion. As You said, stamps were casted and bar's sides were mechanically processed. On the other hand material is indeed old, so it is probably kind of old replica or counterfeit. Fortunately I can still return this item and get money back. I've also learned bunch of very interesting knowledge about Cho Gins. Thank You All so much for help regarding this. Edited by Miguel_85 10/27/2023 07:42 am Report this Post to the Staff
gxseries Pillar of the Community Australia 3831 Posts	Posted 10/27/2023 12:14 pm This is an example of chogin that I have. Issued a lot later: 1837 - 1858. Weight: 149.62g My partial coin collection http://www.omnicoin.com/collection/gxseries My numismatics articles and collection: http://www.gxseries.com/numis/numis_index.htm Regularly updated at least once a month. Report this Post to the Staff
Miguel_85 New Member Poland 13 Posts	Posted 10/28/2023 5:11 pm Nice bar! I wish to get one someday :) Report this Post to the Staff
	Replies: 7 / Views: 1,701

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