On November 21, 887 AD, Fujiwara no Mototsune recommended to Emperor Uda to became Crown Prince from commoner status. For this throne, Emperor Uda gave an imperial message to Fujiwara no Mototsune for assign as the Kanpaku (Emeror adviser) but he refused this assign. The Emperor send another request with comment and it was "request you as Ako". The meaning of Ako is just a rank without any official duties. This is same meaning as useless person with high rank. This imperial message triggered the Ako Controversy.
In April 888 AD, the Emperor Uda order to experts about make sure that Ako is not doing any duties. But the experts were afraid of Fujiwara's influence so they did not complete their duties. In June, Emperor decided to cancel the imperial orders, which is considered the "first real setback of his career".