Inner Sanctum

A pretty good route if you climb it so as to avoid some lichen and loose rock, but not quite as direct that way.

P1 (5.9, PG-13, 150')

Climb up the initial left-facing corner to a lower angle section of rock and progress back into a right-facing open-book. Place some gear and work up and left out of the steep corner. Follow the corner directly (lichen and thin pro, 5.9+) or stay left out of the true corner on the face (big holds, thin pro, 5.8+). Go out around the corner and into a second, very short, right-facing corner. and onto a tiny ledge above it. Pull onto some good holds above (5.8+, PG-13) which are just left of a bulge and then move out and right on easier climbing (5.5, S) to the top. Belay from gear in horizontal cracks.

To retreat, we climbed down the South Chimney (5.5+), but it might be less enervating to climb up the slab of the main rock for 50 meters to the S.W. Chimney. And descend that route, or to finish on a slab route to the main summit and a standard descent.

Arrive at the Upper South face of the 3rd Flatiron in the vicinity of the S.W. Chimney and S. Chimney. Just downhill from the SW chimney, perhaps 50 meters and just 15 meters right of the pocketed dihedral that is the start of the South Chimney, there is a shallow, blocky, left-facing dihedral starting at the ground and rising up over a lower angle section to a right-facing steep corner. This is the start of Inner Sanctum. Just right of this is the offset overhanging seam and flake start to "Thin Crack."

A standard light rack to 3"