The final four semi-finalists face two intense challenges set by the judges in a bid to make it to finals week. They have the privilege of experiencing demonstrations by respected Michelin-starred chef Andrew Wong. His London restaurant, A. Wong, is regarded as the most cutting-edge Chinese restaurant in Britain today. In his demos, Andrew gives the chefs a taste of his mission to expand the culinary understanding of Chinese cuisine by showing them two dishes, dim sum and crispy chilli beef. The chefs then face an invention test in which they must take on board and use the ideas and techniques learned from Andrew. They have one hour and 30 minutes to produce two dishes and present them to Andrew and the three judges for them to taste and critique. The favourite chef of the day will be rewarded with a pass straight through to finals week.The three chefs who remain must cook off to make it through. They have 90 minutes to create a two-course signature menu of an exceptional standard. Judges Marcus, Monica and Gregg will taste their efforts and decide which chef heads home and which two will join the other chef to complete the finals week line-up.