On the Leaf Village Arena level, 1st Area (first level where you get the wind scroll) near the end of the level, you will fight a jounin-level enemy (big green ninja) and to the right of the platform he is standing on, there is a small crawl-way. Inside of the room, there is a large invisible scroll. When you acquire it, that character will permanatly learn level 4 Jutsus (if you save your game.)