A great compression problem. Start sitting using low hands on either side of the face. Make several tricky moves and slap up the sides to stand. Once standing you can either jump for the top or continue slapping your way up. Top out and step up over other boulders to get back to solid ground to walk down. The tempting rocks to the left and right of this face are off.
From the main trail leading to the Tilted Tree Corridor, continue along the trailside faces of the corridor and then passed the main corridor faces until you reach a shorter, detached rectangular boulder with other boulders stacked on top of it (This boulder is under a large roof that would appear to be the outer back end of the boulder that Roof Problem and Final Fantasy are on. Those routes are on the inside, this route is outside and on a lower tier).