Candidate

If you ask me personally - why should I ? I have one in UNC (I owe it since 1975 or so). And if I didn't have - I'd rather search for one in better condition, and pay maybe $200-$250 for AU or UNC. But there are collectors who can not afford to pay $200, so they may buy this particular one for up to $100 or even $150 (if they will not notice and have any doubts about possibility of altered date; by the way, the topicstarter did buy it, didn't he?). As for "proof": I'm sure for much more than 50% that this coin was counterfeited (maybe, for 95%). As I wrote before, I'm not an expert in this period, so I can not prove or professionally reason and explain it (especially, with pictures provided). But even these pictures are enough to see traces of some suspicious mechanical damage near last digit of date. And generally in any case when there is some doubt (even a 10% chance) of counterfeit I'd advise to refrain from purchase of this (or any other) coin. If you ask something - you better say "please" next time. I'm not obliged to do any investigation or prove anything to you personally. But (for other participants) here are some links: One (very rude one) on sale on "Molotok" - http://molotok.ru/item1138859531_5_kopeek_...o_original.html Discussion and pictures at web-forum: http://coins.su/forum/index.php?showtopic=46681

Anyway, statement that it is "absolutly unrare coin" is not correct$ it is not "rare", but scarce ("key date") and popular. Also, even in your "book second edition" (2004) there are no varieties of this year listed - so there are no other "variants", which you had mentioned. And "this particular coin" would be "about VF" (imho) and still cost $100~$150, if genuine (but most probably it is not). Counterfeits of other scarce coins of 1961-1991 period (as 20 kopeks 1991 w/o mintmark, 20 kopeks 1976, etc.) are informed about quite often; I noted such reports in web-forums, etc. - even though I'm not really interested in coins of this period.

I'm afraid you are not well informed in this case (at least less informed than about past auctions catalogues). In the "only-one-you-believe" work by Fedorin (3rd edition) there are no varieties of this coin, only one main type (Fedorin listed it at "50 ye"). 5 kop. 1970 is the most scarce date out of 1961-1991 series, and it's current market value is around $150-$200 in VF-XF condition. So there is some reason to counterfeit it: simply in order to transfer "50 cents" (actually, even less than that) into $150.

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And lots of fakes too... I'd suggest that you also show your coin's edge - and then ask some knowledgeable person to give his opinon... I'm not an expert in this type, but it looks a bit suspicious to me... but maybe just well cleaned... (All imho and sorry if it is a false alarm...)