Starting from the beginning square, did some more exploration of the brown woods area to the west. Found some more "Secrets to everybody", bought another potion refill, went to the southwest most square and found a dead end with an old man in a cave that says:
Go north, west, south, west to the forest of maze.There it is, that's how you get through the lost woods without using a guide, and get to the graveyard. Touching the graves makes a ghost appear... but if the armos statues have taught you anything, you know that one of these graves probably moves to reveal a staircase... yep.
Master using it and you can have this.Magical sword get!
Found the 6th dungeon after that, very easily.
Level 6 - Dragon Dungeon
Aim at the eyes of Gohma.This dungeon introduces wizzrobes... both the red and blue variety. The blue kind moves around the room while shooting at you, the red kind only teleports around and is way easier to avoid. They get really annoying when they're combined with other enemies in the room.
The first part of this dungeon is very linear... but its difficulty is mostly from the enemies. I think the game meant for you to have the magical sword by this point because otherwise this dungeon would be a huge difficulty spike...