- Born: 1671
- Died: 1723
- Other Names: 亮直 (Liàng zhí)
- Chinese/Japanese: 徐 葆光 (Xú Bǎoguāng / Jo Hokou)
Xú Bǎoguāng was originally from Changzhou in Jiangsu province. His zi (J: azana) was Liàng zhí. He was tanhua (third-highest scoring) among the candidates who took the capital-level Chinese imperial examinations in 1712; Xu then became a member of the Hanlin Academy.
Seven years later, in 1719, he served as deputy envoy on a mission to the Ryûkyû Kingdom to perform the official investiture of King Shô Kei. The lead envoy was a Manchu official named Hai Bao. The envoys stayed in Ryûkyû for eight months (from 1719/6 to 1720/2), the longest any Chinese mission ever remained in the islands. This mission saw the first ever performances of kumi odori. In addition, a dispute broke out between the Chinese party and Ryukyuan officials, led by Sai On and Tei Junsoku. The kingdom had gathered only 500 kan of silver to purchase goods brought from China for trade, but the mission unexpectedly brought 2,000 kan worth of goods, including jades, spices, porcelains, clocks, antiques, and scrolls of calligraphy and painting by famous artists of the Song, Ming, and Qing dynasties. In the end, Sai On negotiated a settlement, paying 600 kan for all of the goods. The 1719 mission also included 600 additional people, including cartographers who set out to map the archipelago.
Despite these disputes, Xu is known to have maintained a lifelong friendship with Tei Junsoku after this mission, and to have donated some amount of funds to the King of Ryûkyû to help improve the Confucian temple in Shuri.
The official report and record of the journey compiled by Xu Baoguang in 1721, entitled Zhongshan chuanxin lu (J: Chûzan denshin roku), quickly came to be regarded as one of the chief sources on Ryûkyû, and remains an important historical document today. The text describes the journey to Ryûkyû, various rituals and ceremonies including the investiture ceremony and formal banquets, as well as the topography, political structures, customs, and language of Ryûkyû. Its diagrams of the maritime distances between Fuzhou and Naha, and between Naha and various other locations in the Ryûkyû Islands, may be the earliest extant such record.
Xu's report was first published for a more popular audience in 1765, and was later not only re-published in both Edo and Kyoto, but was even translated by a French missionary, becoming a valuable source of information on Ryûkyû for a Western audience.
The work also served as the basis for multiple later works, including the 1757 Liuqiu-guo zhilue by investiture envoy Zhou Huang, and a handscroll painting (date unknown) by Japanese painter Yamaguchi Suiô, now in the collection of the University of Hawaii at Manoa Library, depicting scenes from the activities of the investiture envoys.
- "Jo Hokô," Asahi Nihon rekishi jinbutsu jiten 朝日日本歴史人物事典, Asahi Shimbun-sha.
- Some sources say he died in 1740. Schottenhammer, Angela. “Empire and Periphery? The Qing Empire’s Relations with Japan and the Ryūkyūs (1644–c. 1800), a Comparison.” The Medieval History Journal 16, no. 1 (April 1, 2013): 175n98.
- Ch'en, Ta-Tuan. "Investiture of Liu-Ch'iu Kings in the Ch'ing Period." in Fairbank, John King (ed.) The Chinese World Order. Cambridge: Harvard University Press, 1968. pp135-164.
- Yokoyama Manabu 横山学, Ryûkyû koku shisetsu torai no kenkyû 琉球国使節渡来の研究, Tokyo: Yoshikawa kôbunkan (1987), 226.
- Katrien Hendrick, The Origins of Banana-Fibre Cloth in the Ryukyus, Japan, Leuven University Press (2007), 54.
- Schottenhammer, Angela. "The East Asian maritime world, 1400-1800: Its fabrics of power and dynamics of exchanges - China and her neighbors." in Schottenhammer (ed.) The East Asian maritime world, 1400-1800: Its fabrics of power and dynamics of exchanges. Harrassowitz Verlag, 2007. p46.
- "Ryukyu Kokuo Sappo No Zu," Treasures from the University of Hawaii at Manoa Libraries.