The Imperial Court thought that Kukai, who was supposed to study overseas for twenty years, came back only two years after his departure from Japan, broke the regulation and did not allow him to come into Kyoto until 809.
20年の留学予定が僅か2年にして帰国した規則違反の空海に対して、朝廷は大同4年（809年）まで入京を許可しなかった。