Intermission (5-6)

With the Ladder, suddenly a whole bunch of Heart Containers will be available to get. So let's get them. The first one is at C-3. Use the Ladder to cross the river near Dungeon 2 and make your way here. Bomb the wall and get the Heart Container from the Old Man.
The second one is along the beach. Just cross over the docks and pick it up.
The third one is near where you started your adventure. Two spaces left of where you got the Wood Sword. This is the last hidden Heart Container. The rest are from dungeon bosses.
Now for Dungeon 6. Remember where you got your first Heart Container? Return to H-7. If you've reached at least :35 on the clock, you should notice an Ocarina square in the sand. Play the Ocarina and Dungeon 6 will magically arise.