It was the original Beijing Capital Airport, when the new terminal was opened in 1998 (maybe 1999), it was closed but then re-opened as T1, with the new terminal being T2. Of course T3 was added later. Back in the early/mid 1990s, it was quite an experience, I think there were only three luggage carousels for international arrivals, but it actually worked pretty well, all things considered.....