In Japan, we have a custom to appreciate the moon, especially the full moon in September. We set dumpling and seasonal fruits out by the window and watch the moon. This custom is called TSUKIMI. TSUKI means the moon, and MI means watching. The prototype of tsukimi for the Japanese, who are a farming people, is to liken the moon to a divinity and to pay for abundant subsequent harvests of ripened rice. So we hardly do it in this traditional way now, but still we say "It is the season of Tsukimi".
We know from our patrimony that a rabbit lives in the Moon and cooks rice cakes there. You can see designs with the moon and rabbit together often, like this, this . And since the round yellow part looks like the moon, we call this way of making eggs "Tsukimi". This is Tukimi Udon. And Japanese McDonalds sells Tsukimi Burgar . This is a McDonalds season special only in Japan.