Otto reached the halfway mark at the Royal Cape Golf Club on a total of 10-under-par 134, with Tjaart van der Walt and Omar Sandys on six-under-par.
Jared Harvey, Justin Harding, Desvonde Botes and Allan Versfeld were another two shots back on 140.
Otto, who has 12 Sunshine Tour titles to his name, used the experience to his advantage as he went around the 6260 metre course without dropping a shot.
Otto started his round on the 10th, and did not make a birdie until he reached the 16th.
He then made three in a row, and another after the turn on the second, for good measure.
Van der Walt and Sandys had seven bogeys between them three for Van der Walt and four for Sandys which made keeping Otto within striking distance more difficult for them when the weekend’s play starts.
Otto’s four-under was matched by Ruan de Smidt, Gert Myburg and Ulrich van den Berg, whose 68 was spoiled by a bogey-bogey finish which left him eight shots off the lead.
– Sapa
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