You could do SFO-NRT-PVG-ICN-KIX-SFO, or SFO-NRT-PVG-SFO, or nest a round trip ticket to HKG/SIN/ICN so it would be SFO-NRT-PVG-ICN/HKG/SIN-PVG-KIX-SFO.
Some suggest you could buy a refundable one way ticket, and cancel it. I'm not sure how that works.