restrictions on the experts of high level chip technology to try to slow china s advance in advanced technologies, those are pretty important and china doesn t like those but in retaliation just two days before yellen s visit china imposed license restrictions, export licences on two key minerals which everybody needs us both sides have a lot at stake here white thank you. thank you very much for your thoughts. antony blinken did the visitor about a month ago and when he got back president biden overheard calling present shejinping a dictator so that visit didn t end very well but maybe this will be more successful. yellen is landing in a few hours time so we will see how that goes. you re watching bbc news here with