In reply to Frank4short:
Completely endorse Alastair's reply - was going to say "have you seen a picture of it?" but he already did that! From memory {1978) getting off Asgard's summit plateau - possibly 2 or 3 football pitches in area (in contemporary references - I'm not that keen on football!), and roughly triangular, involved guessing more or less where the Swiss route came up, then scrambling/climbing down to a ledge system just below the top and looking for anchors; these were in situ, obviously, otherwise the first (and any subsequent) ascensionists would have still been up there! A couple of steep (ie nearly vertical) abseils led to the notch between Asgard's two summits, then three lower-angle abseils brought one down to the top of a slightly unstable snowfield and the start of relatively easy ground. I don't know what grade the Swiss route goes at, but I would imagine that there are pitches of four or five.