An easier question is "when":
I arrived, for the first time, almost exactly four years ago, in late April of 2009.
I lacked even basic knowledge about the place in April of 2009. I lacked experience teaching. I lacked experience with East-Asians, besides a few acquaintances here-and-there. And I didn't know what I was getting myself into.
Four years on, the memories of my first night in Korea are vivid. They are more vivid than many of the things I did just this past weekend! In the coming posts, I will write down my memories of that first night.