Final answer:
The expansion of the Koori court refers to the increasing influence and power of the Koori court in the Japanese government.
Step-by-step explanation:
The expansion of the Koori court refers to the increasing influence and power of the Koori court in the Japanese government. The Koori court was one of the powerful clans that served the Yamato court in specialized ways. They may have been put in charge of diplomatic relations with the peninsular kingdoms. The expansion of the Koori court would involve them gaining more authority and responsibilities within the government, potentially extending their influence in different areas.