4 ideas
When the rebel Huang Chao took Guangzhou around 878, the account reports that about 120,000 foreign Muslims, Jews, Christians, and Zoroastrians were killed and the mulberry groves that fed silk production were cut down. The disorder ended regular Gulf sailings to China. Merchants moved their meeting point to Kalah on the Malay peninsula, where Arab and Chinese ships met halfway. One political shock at a single hub reorganized an ocean-wide trade network.
At Guangzhou, officials unloaded incoming cargoes into warehouses and held them until the last ship of the season arrived. They then took a fixed share, about thirty percent, as duty and released the rest to the owners. The ruler had first right to buy goods but paid the highest market price promptly, so the heavy levy stayed tolerable because it was known in advance and paid fairly.
Travelers in China carried passes from the governor and the eunuch official listing their name, origin, and goods, so lost property or crimes could be traced along the road. Loans were set down in written bonds marked by the borrower's fingers, and a debtor who denied the debt was confronted with his own document. Paperwork let a vast empire enforce accountability between people with no personal ties.
Abu Zayd presents his continuation as a correction and update of an earlier set of reports. He adds material heard from reliable travelers, such as Ibn Wahb of Basra, who described an audience with the Chinese emperor. He also says he leaves out sailors' stories he could not confirm. Knowledge of distant lands is treated as testimony to be weighed by the source's credibility, not as marvels to be collected.