I picked this rarity up at Hwadong Auction in Korea in October 2019. Dr. Norman Jacobs was a Japanese linguist in the Army and built up the most complete collection of Korean and Japanese rarities, specimens, and pattern coins during this time in Japan post-WW2. He used friendships, networking, and Japanese language skills to save many extreme rarities "to rescue some of the Osaka Mint coins and patterns that would have otherwise been melted by U.S. forces." (Source:
CoinWorld)
He passed away in 2004 and his collection was sold in 2011 via
Heritage Auctions netting nearly $7M. Of his collection was the absolute King of Korean rarities and the #4 coin in HA's World Coin Hall of Fame: The 1909 20 Won gold coin. This alone sold for $632,500 and only two are known to exist.

Thus, when his 1888 5 Mun copper coin came up on auction, I had her in my sights. If I was going to walk away with anything that day, it would be that coin. My son and I fought off three other Korean bidders there and got exactly what we wanted:

One thing to note is that this coin is actually a rotated dies error as well. Even though it seems a few degrees off in the holder itself, the reverse is definitely rotated at least 95 degrees. I wonder if I send this in to get the error designation, could I keep his collection label?