since this is a confusing topic I thought I´d try to explain the visa exemption rules in simple terms.
Please note that this is no legal advice but rather the information I collected before travelling to Shanghai myself under the 144 hour visa exemption rule. Please doublecheck if you are citizen of a country to which the rule applies.
In simple terms the 144 hour visa exemption can be called the three country rule.
You need to travel from country A to country B (China) and leave