Gong Dao Bei
The Gong Dao Bei 公道杯 ("Justice Cup") is used as a secondary vessel, a place to hold tea that has been decanted from the primary vessel. This allows for precision timing - the steeping process can be halted at the perfect moment and consolidated in the Gong Dao Bei to make sure that every cup is the ideal concentration. These can also be used as a reservoir to cool the water to the proper temperature before steeping the tea.