10 events the sources record for this year, grouped by region.
What happened
China (4)
Emperor Wenzong received congratulations at Xuanzheng Hall, granted a general amnesty, and changed the era to Kaicheng. (Old Book of Tang (Jiu Tangshu), Annals 舊唐書 卷17下 開成1年 1月)
In intercalary fifth month, in case the Tang embassy's ships drifted onto Silla, the court followed old precedent and sent notice ahead to Silla's Shiji-shō (Office of Affairs); Ki no Mitsu was dispatched as envoy. (Shoku Nihon Kōki 續日本後紀 卷第五 (원문 68번째 단락))
In August the Dazaifu reported urgently that sixteen sailors of the third Tang ship had drifted ashore on floating planks. (Shoku Nihon Kōki 續日本後紀 卷第五 (원문 96번째 단락))
In December the envoy to Silla, Ki no Mitsu, reported back; because Silla's Shiji-shō repeatedly questioned him with suspicion, he could not properly deliver his mission and returned, and he was rebuked. (Shoku Nihon Kōki 續日本後紀 卷第五 (원문 134번째 단락))
Japan (6)
In February, for the Tang envoys, a rite was held at Kitano for the heavenly and earthly deities and government business was suspended. (Shoku Nihon Kōki 續日本後紀 卷第五 (원문 12번째 단락))
In May a violent gale and heavy rain blew through the night; the Tang-bound envoys' ships were anchored at Wada Harbor in Settsu, so a kantoku guard was sent to check on their safety. (Shoku Nihon Kōki 續日本後紀 卷第五 (원문 57번째 단락))
In July a courier by relay post reported that the ship of vice-envoy Ono no Takamura had drifted and reached Betsujima in Matsura District, Hizen Province; an imperial tally (chokufu) was issued. (Shoku Nihon Kōki 續日本後紀 卷第五 (원문 95번째 단락))
In August the Dazaifu reported urgently that, as the envoy to Silla departed, the third Tang ship had drifted to Nanpo in Kamitsushima District, Tsushima, with only three men aboard. (Shoku Nihon Kōki 續日本後紀 卷第五 (원문 105번째 단락))
In September the Tang envoys and deputies entered the capital from the Dazaifu and returned their sword of office, marking the failure of the first voyage. (Shoku Nihon Kōki 續日本後紀 卷第五 (원문 111번째 단락))
In October the envoy to Silla, Ki no Mitsu, returned to the Dazaifu. (Shoku Nihon Kōki 續日本後紀 卷第五 (원문 120번째 단락))