Walk straight up until the screen changes, then go straight up one more screen and stop.At this point, Link should disappear, now under and inside of the wall.Wait for the blue guard to turn around (or slash him once to get his attention), then press left on the D-pad to continuously run up against the left wall just as the guard hits you.Go up the stairs again, but this time exit through the door to the left.If you do, you’ll need to repeat the last step. Reload your save and make your way back into the castle, but make sure you don’t touch any of the guards along the way.Hop off the ledge and press ‘Select’ mid-air, then choose to save and quit the game.
Once inside the first main room, climb the center steps and walk to the ledge just to the left.Start a new game and head to Hyrule Castle to your sword, then follow the path to go in.