IGN: Was it always the plan to be told in this manner? As two parts or even three-parts? Or is this the result of something that happened after the game had already been released?

Kitase: No, it wasn't planned - as mentioned in the previous answer, it was triggered by fans reaction to "Eternal Calm."

Toriyama: When we were working on FFX, there were no talks about a sequel. However, after completing FFX, we thought it would be nice to create a new story in this same world some day. Personally, I wanted to create a game where one could revisit the world and the characters - say, maybe once every two or three years. So, it was quite meaningful that we were able to do a sequel with FFX-2.