Hamburg is 7 hours behind Shanghai
Best overlap: 3:00 PM to 6:00 PM in Shanghai is 8:00 AM to 11:00 AM in Hamburg.
Keep meetings inside 3:00 PM to 6:00 PM in Shanghai — that maps to 8:00 AM to 11:00 AM in Hamburg. Hamburg is 7 hours behind Shanghai, leaving about 3 hours of daily overlap — enough for most meetings if you don't leave them too late in the day. Remember that Hamburg shifts for daylight saving and Shanghai doesn't, so recalculate the overlap after each clock change.