
The door leads to a small secret room where a treasure box contains the Whistle. The second Magic Whistle is obtained by flying above the ceiling at the end of the first room, where there is a door hidden above the top of the screen. Behind the curtain is a secret Toad House, whose single box contains the Whistle. The first Magic Whistle is obtained by holding the down button on while standing on the white block at the end of the level, so that Mario or Luigi drops behind the background, and then quickly getting behind the black curtain at the end of the level before the white block's effect wears off. However, only two are needed to warp directly to World 8. However, in the original Japanese version, a glitch in World 5-1 allows the player to obtain a fourth Whistle. There is a total of three Magic Whistles that can be collected from treasure boxes: two in World 1, and one in World 2. Using the Whistle in World 1 allows Mario or Luigi to warp to World 2, World 3, or World 4 using it in World 2 through World 6 allows him to warp to World 5, World 6, or World 7 and using it in World 7, World 8, or World 9 allows him to warp to World 8.

3, using a Magic Whistle summons a whirlwind that takes Mario or Luigi to World 9, the Warp Zone, where the player can skip ahead to the start of a later world.
