Annals Shoku-Nihongi retains some records in its article of the year when Buddhist priest Dosho deceased about words of Xuanzang once given to Dosho. According to that story, Xuanzang especially cherished Dosho, let him live in his own room and told him:
“Once I traveled through Xiyu, I suffered from hunger, but I had no one to beg for food. Then suddenly there appeared a priest with pears in his hand, gave them to me to eat. I ate these pears and day after day I recovered health. Now, you resemble to that priest.” The annals rationalizes that Xuanzhuan overlapped the image of his past benefactor with that of Dosho.
Further he said,
“Sutras and commentaries are deep, unexhaustibly difficult. Rather, you have better study Zen and to spread it to eastern country, Japan.”
He encouraged Dosho to engage in the practice of Zen and Dosho complied with this advice. When returning to Japan, he was presented by Xuanzang sarira, sutras, commentaries and a cauldron that Xuanzhan obtained in his journey through Xiyu and protected his life.
On his way back to Japan, Dosho by this cauldron treated and gave food to those suffering illness, but in the return journey as soon as he got on board, the good ship could not proceed a mile and he was told that the sea god dragon king had wished the cauldron and the cauldron be thrown into sea. Dosho is said to have complained why the dragon king wished only the one donated by Xuanzhan but had no other choice than to give up the cauldron.
The above was excerpted from this source: Ethnogenesis of Japan