So, what IS the historical background and etymology of gujeong? I read in a rather reliable place that it's "actually pretty involved and can be fascinating." :)
First of all, happy new year of the Rabbit for you and everyone. Today is the Lunar New Year's Day. (Please don't call it Chinese New Year. Koreans, Vietnamese, Mongolians and other Asian countries also celebrate the Lunar New Year.)
The Korean already explained Korea's traditions surrounding Lunar New Year in this post. But this question is about the name by which Koreans call Lunar New Year -- gujeong. Why is this word interesting? Because the word means "old new year." Then what is the "new new year"? Why is there an "old new year" and "new new year" in the first place?
Answer: Japan. Traditionally, Korea has celebrated the Lunar New Year. But Japan celebrated the solar new year by 1910, when it annexed Korea. After the annexation, Japan imposed the "new new year" -- what is now referred to as shinjeong. (By now, you might have guessed that gu means "old," shin means "new" and jeong means "new year.") After the liberation, majority of Koreans went back to celebrating the "old new year," although some number of families remained celebrating the "new new year."
Again, happy new year to everyone! Here is a nice bowl of tteokguk (rice cake soup) for the occasion.
Got a question or a comment for the Korean? email away at firstname.lastname@example.org.