However as long ago as 1995 TŌNO Haruyuki cast doubts on this way of telling the story, at the same time as questioning another long held belief: that the Japanese Emperors presented themselves as equals to the Chinese Emperor, and that the Chinese went along with this. This latter is interesting because it sheds light on the nature of the embassies sent from Japan.
Tōno shows that there is evidence to throw doubt on the supposed equality of the two emperors. It is true that as early as 607 a mission to the Sui dynasty emperor Yang-ti (隋煬帝 ) presented a letter which described the Japanese emperor as Son of Heaven, the title of the Chinese Emperor, however Yang-ti saw this as an affront.
Tōno's article concentrates on the embassies to T'ang China. In 632 a Chinese imperial envoy clashed with the Japanese court over protocol and did not read the letter from the Chinese Emperor. Tōno suspects that this was an attempt to subdue the Japanese. Note that this was a period of massive expansion westwards, with Chinese troops pushing on past the Tarim basin, where they were stopped by an Arab army also intent on expansion. It was the time of the greatest extent of the Chinese Empire.
Until 663 the Japanese were influential in the Korean peninsular. However in that year the Paekche (from whence Buddhism was introduced into Japan in 552) were defeated by a coalition of the T'ang and Silla, despite being shored up with Japanese forces. In 668 the alliance defeated the Koguryo thus unifying Korea. Although the Japanese continued to see Po-Hai (in present day Manchuria) as a tributary state, Tōno points out, from this time onwards it would not have been possible for the Japanese to insist on equal status. Indeed the embassy of 671 can be seen, according to Tōno, as a declaration of surrender!
After a break of 30 years another embassy was sent to the T'ang court in 702. It was at this time that the Japanese concede to paying tribute every twenty years. This was a pragmatic move on the the part of the Japanese in the face of a rampant T'ang state in the process of crushing opposition in other quarters. Evidence of this promise, more or less hushed up at home, is seen in a letter from a monk on Mt T'ien T'ai who is asking for permission to pass on information to the Japanese monk Ensai in 840 where he mentions that "... and they [the Japanese] have promised to pay tribute once in twenty years" (p.45). This would not have been common knowledge in Japan, and though careful records of many other occasions were kept, letters from the Chinese Emperor were mostly lost. In one letter from the Chinese Emperor 735 begins by writing "I order the king of Japan..." (p.52).
It obvious that in the Japanese mind Japan was the centre of civilisation. The ritsuryō code for instance, despite being modelled on a T'ang Chinese legal code, refers to other nations including the Chinese as barbarians. Tōno cites the fact that no one of the royal family ever went to China as this would have admitted to the Japanese people that they were subordinate.
Although Tōno does not mention it, we could also comment on the relative weakness of the Japanese nation until the reforms of Kanmu began to take effect. Japan had been essentially bankrupted by a succession of natural disasters and the flurry of temple building that ensued as a remedy, and by a number of expensive and sometimes disastrous military campaigns against the Ainu. In Kūkai's day there was forced labour and military service. Many people were homeless, and farming so difficult that many left the land to become beggars. In the face of a strong and dynamic T'ang Japan would have looked weak, and perhaps it is only the long sea distance that prevented them from being assimilated along with other neighbours.
Tōno's conclusion is that the embassies to the T'ang court were to offer tribute as agreed in order to keep the Chinese Emperor from casting a military eye eastwards. It is this fact which gives us the clue to why the embassies were sent when they were. As I mentioned it is common knowledge that Summer is a bad time to sail to China; and it is assumed that the Japanese were simply ignorant of the seasonal winds. However Tōno reminds us that emissaries from the Po-hai state regularly visited Japan at the time, and judging by their arrival and departure dates they were adept at using seasonal winds. (p.58) Tōno also argues that the Japanese ships were more sophisticated than has previously been thought, that they used cloth sails in addition to bamboo matting. However they did lack keels which meant they could not use the sails unless the wind was behind them.
The offering up of tribute to the Chinese court was ideally done at the New Year celebrations - the Chinese year beginning on the second full-moon after the winder solstice, usually sometime in February. The average travelling time to China for all of the missions, which can be worked out from a chart in Tōno's article, was six months. This meant leaving in the 6th month, or late summer (July or August) in order to arrive in time for the ceremony in January or February. Far from being ignorant of nautical and seasonal knowledge the Japanese probably knew exactly what to expect, but were forced for political reasons to attempt the crossing at this time. The knowledge of what to expect was probably what accounted for the reluctance of Japanese officials to go on such trips.
After Kūkai's trip in 804-6 only one more Embassy was sent to the T'ang court. Perhaps this was because it was clear, even in 806, that the T'ang dynasty was falling apart. It staggered on until 906 but was racked by civil strife and war. In other words there was no longer any threat to induce a offering of tribute, and Japan had gotten onto a firmer footing as well. Thanks to Kūkai the Heian period was one of a flowering of Japanese culture as distinct from imported Chinese culture.
TŌNO, Haruyuki. "Japanese Embassies to T'ang China and their Ships," Acta Asiatica. 1995 v.69: 39-62.image: Illustration of a Chinese ship of the type that would have visited Japan during the Edo period (from Tōno article).