The terrace e e is easily reached from the screes. From it there are two definite climbs, one b b up a gully to the left, that leads out on to the east arête, the other c c up a more open gully that passes to the summit ridge. It is possible that the notch between the great tower and the east arête can be reached from this side, but the upper part looks difficult.
The east arête was climbed in about 1888 by the writer. The first recorded ascent was in January 1891 (H. K., W. E. S., and O. G. J.), and the first ascent by a lady in August 1891 (Miss L. G., K. W. D., and O. G. J.)
It can be followed all the way up. The tower is best turned on the right, and the vertical wall of 40 ft. that immediately follows is climbed direct from the little gap, with just a slight divergence to the left. The only serious difficulty on the arête is a wall of rock 100 ft. higher up. It can be surmounted by a thin cleft, the jammed stones in which are unsafe; or by working up the face a little to the left. The situation is very exposed. This, and any other bad bits, can generally be avoided by climbing down to the scree gully on our left. Near the top of the arête we pass the exit of the chimney b b, which descends steeply to the right.
The north arête has probably not been climbed, but the gullies on each side have been taken. They call for no special comment. The one to the right is worth ascending for the view of the fine rocks on this face. It is mostly scree with a small pitch near the top, and was once marked above by a little cairn. It is admirable when hard snow is about.
The gully c c to the left is very open and risky, consisting of a series of shelves formed by the falling away of the porphyritic pillars that characterise the face.
The climb b b is rather better. The scrambling from the terrace is easy but steep, until a large overhanging boulder entirely blocks the way. We then climb up the vertical wall on the left and traverse back to the gully. It finishes very abruptly on the narrow upper ridge of the east arête, and in a most unexpected way we find ourselves looking down to Llyn y Gader with the face of Pen y Gader directly opposite.
There are a few short climbs on the face of Tyrrau Mawr, but nothing very definite can be picked out.