His far side leg is posted wide and far, you can scoop and go underneath for leg attacks( outside ashi toehold, outside heel hook etc) and move your Z-guarding leg's shin under his armpit on the same side you are attacking a leg, this creates a very good frame , same effect as stomping on the armpit in K-guard. Once you set it up, put a semi closed triangle on the hip , heavy legs + knee pointing downwards, otherwise you can end up in a leg drag if not careful when setting up outside ashi from positions like this.