Oh, fair enough, last time I looked into the China regions that didn't exist. Reading the announcement I'm loving the seeming contradiction between " AWS KMS is a managed service that makes it easy for you to create and control the encryption keys used to encrypt your data, and uses Chinese government-approved hardware security modules to protect the security of your keys." and the very next sentence "The service is designed so that no one, including KMS service operators, can retrieve your plaintext master keys from the service."

Something tells me those master keys aren't quite as secure as you'd expect in other regions.