Who can tell me the specific time of nineteen Japanese envoys to China?

In the history of Sino-Japanese exchanges in the Tang Dynasty, the Japanese imperial court sent 19 envoys to the Tang Dynasty, but only 13 actually arrived in the Tang Dynasty as envoys. The other six times, some failed to make it after the appointment, some were "Tang ambassadors" who specially welcomed Japanese envoys to China, or "Tang ambassadors" who accompanied Tang envoys to Japan.

These 13 dispatches to the Tang Dynasty can be divided into four periods: the first four periods are the first period, from Japanese Ming Di (629 ~ 64 1) to tomorrow Qi (655 ~ 66 1), and the Tang Dynasty was in the reign of Emperor Taizong. These four missions lasted for more than 30 years. During this period, the mission was small and understaffed. In the first period, the route taken by Tang envoys was mostly North Road, also known as Silla Road, that is, sailing along the west coast of the Korean Peninsula, crossing the Yellow Sea and landing on the Shandong Peninsula; Or continue to sail along the east coast of Liaodong Peninsula, then cross the mouth of Bohai Bay and land from Shandong Peninsula. At this time, it is safer for ships to sail near the coast, but it takes a long time, and each voyage takes forty or fifty days.

The second period, including the fifth and sixth diplomatic envoys in Tang Dynasty, was the period of Japanese Emperor Tianzhi (662 ~ 67 1). Although the routes and missions taken in these two periods were similar to those in the first period, their political significance was quite different, and they were all diplomatic activities with national strategic intentions. Among them, the fifth mission to the Tang Dynasty in 665 was probably to send envoys to the Tang Dynasty for repairs. At that time, shortly after the Sino-Japanese naval battle at Baijiangkou, the Tang Dynasty shifted its strategic focus to conquer Koguryo in the north, hoping to make peace with Japan. Because of the defeat, Japan was afraid that the Tang Dynasty would attack its own land and welcomed the initiative of the Tang Dynasty. Therefore, when the envoys of the Tang Dynasty visited Japan, the Japanese side responded to the friendship of the Tang Dynasty and sent envoys to the Tang Dynasty. In 669, Tang Jun conquered Koguryo, and after the Japanese Emperor Tianzhi heard the news, he specially sent the Hanoi whale as an envoy to the Tang Dynasty to congratulate him, apparently to show his friendship with the Tang Dynasty.