DPerdue

A South Korean 1998 500-Won.

At only 8,000 mintage, it is the lowest-mintage business strike in the entire S. Korea series of coins.

How does NGC determine "Altered Color"?

I recently go this Korean coin back from NGC.  

FYI:  For that second book from the left, "Yeolswaepae" is the Korean word for what us English speakers commonly refer to as "Chatelaines." 

The Standards Works on Korean Coins:
These are Left to right:

1. 한국의 고전 Korea’s Ancient Coins by Han Yong-dal 한용달, 2002.

2. 한국의 별전열쇠패 (Korean Charms & Yeolswaepae) by Han Yong-dal 한용달, 2007.

3. Cast Korean Coins and Charms by Op den Velde and Hartill, 2013.

4. South Korean Coins in the Era of Development by Mark Lovmo, 2022.

(These are my own photos of the front covers of these texts)