From card: "White silk with the "Yin-Yang" symbol (t'aeguk), two comma-shaped spirals filling a circle in red and blue, and four geomantic signs from p'algwoe (eight trigrams) at the four corners of the flag, the flag was adopted in 1882. Korean flag is generally known as "t'aegukki" (CSH). Changes and additions to card by CSH [Chang-su Houchins] 2-28-85".
Flag E151638, Taegukgi/Taegeukgi, the Korean National Flag, has a different form of 4 trigrams / yin and yang circle from the current South Korean flag. Per Wikipedia contributors, "Flag of South Korea," Wikipedia, The Free Encyclopedia, https://en.wikipedia.org/w/index.php?title=Flag_of_South_Korea&oldid=704919738 (accessed February 21, 2016): The flag of South Korea, also known as the Taegukgi (also spelled as Taegeukgi), the name literally means "Taeguk flag". It has three parts: a white rectangular background, a red and blue Taeguk in the center that symbolize a balance, and four black trigrams, which are selected from the original eight, on each corner of the flag. Original version used by the Korean Empire was designed in 1882 and officially adopted January 27, 1883. Flag E151638 was collected in 1884, and is in the form of the original version. (Current version of South Korean flag was adopted in October 1997.)