Australian David McKenzie is four shots adrift of leader Ho-Sung Choi at the halfway point of the China Open. After starting the day in equal second position, McKenzie slipped down to equal sixth after carding a two-over-par second round of 74 to be two-under overall. McKenzie collected four bogeys and a double-bogey along with four birdies on day two. McKenzie&aposs countryman Scott Strange (one under) is a stroke further back in a share of ninth spot, Aaron Townsend is even while Brad Kennedy and Craig Scott are both one over. South Korean Choi hardly put a foot wrong on his way to a four-under 68 to be six under overall. After bogeying the 1st hole, Choi went on an unblemished 13-hole streak which included six birdies before he bogeyed the 15th. Choi enjoys a two-stroke lead ahead of Chapchai Nirat and Markus Brier who are equal second on four-under. Second Round of the China Open -6: Ho-Sung Choi 70 68 -4: Markus Brier 67 73, Chapchai Nirat 69 71 -3: Gonzalo Fdez-Castano 71 70, Paul McGinley 74 67 -2: Simon Dyson 69 73, Richard Finch 71 71, David McKenzie (Australia) 68 74 -1: Graeme Storm 72 71, Scott Strange (Australia) 70 73, Inder Van Weerelt 74 69 E: Rafael Cabrera 73 71, Carlos Del Moral 72 72, Won-Kyoung Heo 72 72, Chinnarat Phadungsil 70 74, Aaron Townsend (Australia) 73 71 Also: +1: Brad Kennedy (Australia) 72 73, Craig Scott (Australia) 71 74 +2: Kurt Barnes (Australia) 76 70, Ashley Hall (Australia) 75 71, Peter O Malley (Australia) 71 75, Brett Rumford (Australia) 71 75 +3: Marcus Fraser (Australia) 74 73, David Gleeson (Australia) 74 73, Matthew Millar (Australia) 70 77 +4: Mark Brown (New Zealand) 71 77, Chris Gaunt (Australia) 74 74, Michael Long (New Zealand) 73 75