The word gongfu (工夫) means skill applied over time. In tea it describes a method, not a costume.
Where it comes from
Gongfu cha was practised in the Chaozhou and Fujian region from at least the mid-Qing. It spread through the Chinese diaspora through the twentieth century — to Taiwan in the 1970s, and from there into the West in the 1990s.
What travelled first was the apparatus: the small pot, the fairness pitcher, the tasting cup. What travelled slowly was the reasoning behind it.
Why so many infusions
A Chinese tea is not one drink. It is a sequence.
The first steeping opens the rolled leaf. The third is usually the most expressive. The seventh is quieter but sweeter. Brewing once in a large pot throws away the middle of the story.
Why the fairness pitcher
Tea poured straight from a pot is not uniform: the top of the infusion is weaker than the bottom. The chahai mixes it so every cup is the same tea.
It is the least decorative object on the table and the one that changes the taste the most.
The social shape
A gongfu table is small on purpose. Four to six cups, one pot, one person pouring. Conversation happens between infusions, not over them. The pace is set by the leaf.