Ordered by the emperor, Kukai wrote the characters of 応天門 (Oten-mon Gate) on a board to be hung on the Oten-mon Gate of Dai-dairi (place of the Imperial Palace and government offices), but forgot to write the dot at the top of the character 応.
-空海は天皇からの勅命を得,大内裏応天門の額を書くことになったが,「応」の一番上の点を書き忘れてしまった。