Shenzhen is 13 hours ahead of Washington, D.C.
There is no standard 8-to-6 overlap. Someone joins early or late.
The 13-hour difference means Washington, D.C. and Shenzhen miss each other entirely during regular office hours. Where you can, lean on async updates and save live calls for when one team is happy to start early or stay late. Note that Washington, D.C. follows daylight saving while Shenzhen stays put, so the times above drift by an hour seasonally.