In the tenth edition of the Iwata Asks interview series, Legend of Zelda series designer Eiji Aonuma discusses the development process for both The Legend of Zelda: Majora's Mask and The Legend of Zelda: Spirit Tracks, drawing comparisons between the two.

Majora's Mask, Aonuma says, was born out of his disinterest in making the Ocarina of Time Master Quest game. When he approached Miyamoto about this, Miyamoto responded with a challenge: "he said, if we could make a new The Legend of Zelda game in one year, then it wouldn't have to be a "flip-side." In other words, it could be more than a remix of the previous game.

Aonuma elaborated, "At first, we had absolutely no idea what sort of thing we were supposed to make, and we just kept expanding our plans… At that point, the "Three-Day System", the idea of a compact world to be played over and over again, came down from Miyamoto-san and one other director, (Yoshiaki) Koizumi-san. We added that to the mix, and then, finally, we saw the full substance of a The Legend of Zelda game we could make in one year."

Later in the interview, Aonuma and Iwata discussed the thought process that went into the train tracks aspect of The Legend of Zelda: Spirit Tracks. Aonuma discusses a book titled "The Tracks Go On" which he'd read to his son at night. The book discusses a group of children who build train tracks. From there, Aonuma thought about putting a similar concept in the Zelda title. "That's right (laughs). I didn't tell them about the book, I only said, "Let's make it a train." And then, "Let's make it so that you can lay the tracks yourself." I brought it up, and we started from that experiment. But, at first, when I thought it up, I was very casual about the whole thing. I'd say "It would be fun if we could lay the tracks, wouldn't it!" things like that."

Daiki Iwamoto, producer on Spirit Tracks, added "Right. But the problem is that, even if people can lay the tracks anywhere they like, they won't know where to lay them. Then, to make the story work, there are places where you absolutely mustn't go, and other places where you really can't be at certain points in time. So we examined all sorts of different ways of playing. That went on for about a year." When reminded that development for the game was only two years long, Iwamoto added "We spent half of those two years on the railroad. And then, one day, Aonuma-san said, "Why don't we just drop the idea of laying the tracks?"

Aonuma and Iwamoto both agreed that it felt like that was a very major change to take place so late in the development period. When Iwata asked how this was mended, Aonuma commented "In this world, the tracks were there to begin with, but for some reason they've been erased. The player has to put them back to the way they were." Iwamoto added "In other words, somebody's erased these tracks, and Link brings them back together, little by little." Aonuma said that this method was easier to play based on testing. Iwata concluded "If you're completely free, you don't know quite what to do. If your goal is clear, I'd guess that makes it a lot easier to play."

The full interview can be read here.