In all three systems, it is both written and spoken year-month-day, which was the point. Kōki is not used by anyone with a straight face in this day and age.

In all three systems, it is both written and spoken year-month-day, which was the point. Kōki is not used by anyone with a straight face in this day and age. "Mikado Heisei" is an extremely uncommon way to refer to the emperor. "帝平成" gets 724 hits on Google, and "Mikado Heisei" gets 6, in 5 different languages---the first of which is your post above. Even the Japanese-language wikipedia page on him doesn't use the word "帝" anywhere.