Furthermore, in his accounts of the Taiwanese aborigines and Zheng family (entitled 番境補遺, 偽鄭逸事, respectively), he shows his knowledge of those people and lands were extraordinary for his era.
Under the consent of the Fujian officials, Yu travelled to Taiwan following the explosion of the Fuzhou gunpowder stores in 1696 to mine sulfur.
Yu's voyage began at the coast to Xiamen, crossing the Taiwan Strait and coming to a halt in Penghu before arriving in Tainan.
The memoir chronicles Yu's life in Taiwan under Qing rule where he was introduced to the unique culture of the island.
Yu not only recorded the developments of the era, he also took into account the administrative structures passed down by the Dutch and Zheng dynasty.