Via the halfway lochan to the North Face or from the Northface car park and follow the Alt a mullin.
Castle Ridge is the first obvious ridge you come to on the north face
Climb easy rocks beside the gullythat comes from north and south castle gullies. Cross over NorthCastle gully on a large flat area and strike up the ridge direct, taking the easiest line. If in doubt follow the crampon scratches. The are two difficult sections, the first is a short, awkward short chimney and the second is high on the ridge.
The second is the crux of the route and is very exposed. Move from below the wall onto a small ledge the make exposed moves on good holds up a shallow chimney to a good belay. Easily protested with a couple of hex's. Easy scrambling then follows.
N.B the crux is Grade 3 in winter and a little gem.
You can manage with a short rope of 25 meter or double up a 50m 9mm. Protection wise, A selection of rocks, Hex's and a few slings.
For winter Crampons and single mountaineering axe will suffice.
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