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Rotated reverse on Korea proof $1

Are you sure you know what’s in your collection? New error finds prove that sometimes you might not. It never ceases to amaze me that there are some significantly rare and valuable errors that have been squirreled away in collections for decades that are just now being recognized by the hobby and their owners as even existing.

Are you sure you know what’s in your collection? New error finds prove that sometimes you might not.


It never ceases to amaze me that there are some significantly rare and valuable errors that have been squirreled away in collections for decades that are just now being recognized by the hobby and their owners as even existing.

Two coins with values that normally fall within the two-figure range have recently been identified with long overlooked features that could catapult them into the four-figure to five-figure ranges! They are a 1991-P Korean War commemorative proof silver dollar with a 90-degree rotated reverse and a 1973-S Eisenhower dollar, normally struck in 40 percent silver, but in this case, struck on a copper-nickel clad planchet. More of either of these errors could be sitting in anybody’s collection without them even knowing it.
Brad Meadows, senior numismatist for Heritage Auction Galleries noted that the firm recently took in a consignment for a 1991-P Korean War commemorative proof dollar that has a 90-degree rotated reverse die. He acknowledged that it certainly wasn’t the most major error that they have offered, but felt that it was an unusual find saying, “I am anxious to see what kind of response it gets. It still surprises me how things like this can go unnoticed for so long.”

Meadows indicated that the owner of the coin had just found it a few months ago. This is the first example of this error type that I have ever heard on a proof commemorative dollar of any type. It will be offered in an October Heritage auction, though as of press time I am unaware of the specific date.

It should be noted here that even though this error type is most often referred to as a “Rotated Reverse,” it is often impossible to know if it was actually the reverse die that was rotated out of position.

The error type is defined in the Combined Organizations of Numismatic Error Collectors of America Glossary ( as follows:

“Since, under normal circumstances, it is impossible to tell which die has rotated, or perhaps both dies have rotated, the reverse die has been chosen as the offending element. Coins are struck with coin alignment; that is, the top of one side is the bottom of the other side. If a die becomes loose in its holder or was installed with an incorrect alignment, it is said to have rotated. Rotations under 15 degrees in either direction are considered within mint tolerances and have no collector value. The greater the rotation over 15 degrees, the greater the value to collectors. Coins rotated 180 degrees are said to have medal alignment. A couple of recent examples include the 1989-D Congress dollar and the 1988-P Kennedy half, which, by the way, can be found in mint sets.” It should be noted that many foreign coins are normally struck in “medal alignment.”

Jay Fackelman who oversees the online Rotated Die Coin Census Web site (, a census for U.S. coins with major die rotations ranging from 90-180 degrees, said, “Brad contacted me a while back about this piece. It will be interesting to see what it sells for. I wouldn’t even venture a guess as a lot depends on if any commemorative collectors decide they would not mind adding it to their commemorative collection. If it is anything like the (2000-D uncirculated Library of) Congress commemorative (silver dollar), then the price could get up there a little bit compared to most rotated errors. I will be looking forward to see what it really goes for.”

Fackelman followed up later saying, “it is certainly a new experience not only having a new series/date show up so late after issue but especially with it being a proof. Now the big question is, are there going to be any other ones found?

“I would be very surprised if at least one or two more did not show up but with the way the Mint handles proofs compared to regular business strikes there is a chance they could have found some others and pulled them before they were issued.

“At least there is a new item to look for whenever one of these pieces come up for sale either online or in person.”


Error coin dealer, Fred Weinberg of Encino, Calif., said, “First I’ve heard of on this commemorative. Proof – 90 degrees – I’d guess that it would bring around $500-$1,000, or thereabouts. I’ll be interested to see what the others say. As is the case for many error types, a proof rotated reverse could be a hot item for commemorative collectors, proof collectors, as well as error collectors. So you have at least three different groups that might vie for such a coin.”

Error dealer, Neil Osina of Best Variety/Sportscards & Coins, Glendora, Calif., said, “$1000 is not out of the question for major proof errors.”

Alan Herbert, who pens the popular Coin Clinic column for Numismatic News said, “I’d go for $2,500, which is probably low. There can’t be more than three to four thousand, less if they spotted the problem. The 180 degree Congress dollar sold for $2,000 and that was not a proof.”

My estimate of value tends to fall in line with that of Herbert’s and it will indeed be interesting to see what the hammer price on this coin is in October.

On August 28, Numismatic Guarantee Corporation of Sarasota, Fla., posted notice on its Web site ( that it had graded the first known example of a 1973-S uncirculated Ike dollar struck on a copper-nickel clad planchet. This coin, struck at the San Francisco Assay Office, in its satiny uncirculated finish, was offered by the U.S. Mint struck exclusively for collectors in 40 percent silver.

NCG said: “Coins accidentally struck on planchets intended for other issues are known for quite a number of United States coin types, but they are rarely more spectacular than when occurring with dollar coins. This superb gem Eisenhower dollar was struck at the San Francisco Mint for inclusion in the series of ‘blue pack’ silver-clad dollars offered by the U.S. Mint at $3 apiece from 1971 to 1974.

“At first glance it could almost pass for one of these silver-clad pieces, but inspection of its edge (made all the more easy through NGC’s unique EdgeView™ holder) reveals the bright orange-red glow of a copper-nickel-clad planchet! This coin has the satiny texture typical of most silver-clad dollars and confirms that it was struck accidentally as part of that series.

“The Denver Mint was assigned the role of preparing planchets for San Francisco’s production of the “blue” Ikes, but it was simultaneously making planchets of the copper-nickel-clad composition for its own press run of circulating coins. One of these ordinary planchets evidently found its way into a shipment of silver-clad planchets going to San Francisco and was struck and packaged as a silver-clad issue. While this scenario describes how such an error could have occurred, it did not play out very often. This is the first report of a 1973-S dollar struck on a copper-nickel planchet.

“If that weren’t enough to excite collectors, this coin is also a doubled-die obverse variety! It is DDO-2, as listed and illustrated in the book CONECA Attribution Guide to Eisenhower Dollar Die Varieties by James Wiles, Ph.D. This variety, previously known only in the normal silver-clad composition, is now confirmed on a copper-nickel-clad planchet intended for currency strikes. Collectors should check their ‘blue packs’ for more new discoveries.”

It should be noted here that San Francisco also struck millions of the copper-nickel clad planchets for proof dollars that were included in the standard six-coin proof sets that contained the cent through dollar. Thus, the mix-up may not have occurred at Denver at all. If a copper-nickel clad planchet (or more) remained in the bottom of a tote bin that was later filled and used to transport 40 percent silver clad planchets to a press striking the 40 percent uncirculated silver dollars, the wayward copper-nickel clad planchet(s) would have gotten mixed in and could have easily hitchhiked a ride into a press striking the 40 percent uncirculated dollars. Exactly were the planchet(s) got mixed up, we’ll probably never know.

In regard to its value, Herbert said, “I’d go for at least $5,000. Other transitionals have been selling for $1,500 for years.”

Error dealer, Mike Byers of San Clemente, Calif., said, “I’ve handled many Ike off metals, both in Mint State and proof. Also many of the Ike dollar and Kennedy Half transitionals as well. This may be scarcer than the other halves and dollars struck in silver instead of clad, or clad instead of silver, due to planchets being mixed up. I would estimate a wholesale price of $7,500 and a retail price of $10,000.

“As one who has been tracking the values of these transitional type errors over the past few years, my assessment of value is $10,000 for this coin. It will be interesting to see were it ends up when it finally comes up for sale. The hobby will be eagerly waiting!”

Many collectors refer to these “wrong composition planchet” type errors as “transitional errors” since most occur during a transitional period when a coin’s composition is changed from one alloy to another. For example, a few 1943 cents from all mints, which are normally struck on zinc-coated steel planchet, are known to have been struck on copper alloy planchets left over from 1942. While this Ike dollar is not technically a “transitional,” it is often referred to as such anyway.

Readers should note that both of the errors described here are of types of which more could have been made and released to collectors. Identifying them should be easy, simply look for the widely rotated reverse on the Korean dollars and the tell-tale copper-core on the Ike dollars. Let Numismatic News know or contact me directly about what you find at the contact addresses listed below.

I would like to thank NGC and Heritage Auctions for the photos used with this story.

Ken Potter is the official attributer of world doubled dies for the Combined Organizations of Numismatic Error Collectors of America and for the National Collectors Association of Die Doubling. He also privately lists other collectible variety types on both U.S. and world coins in the Variety Coin Register. He is a regular columnist in “Numismatic News”’ sister publication, “World Coin News,” where he pens the Visiting Varieties column. More information on either of the clubs or how to get a coin listed in the Variety Coin Register may be obtained by sending a long self-addressed envelope with 59 cents postage to P.O. Box 760232, Lathrup Village, MI 48076, or by contacting him via e-mail at An educational image gallery may be viewed on his Web site at