Moon Jae In in Beijing to mend frayed ties but may find it hard to put Thaad behind

South Korean President Moon Jae In and his wife Kim Jung Sook arriving in Beijing for the start of their state visit, on Dec 13, 2017.
South Korean President Moon Jae In and his wife Kim Jung Sook arriving in Beijing for the start of their state visit, on Dec 13, 2017. PHOTO: EPA-EFE/YONHAP