"Christmas cakes of this style were originally released by Fujiya, and was popularized when they began sales at Ginza, the central commercial district in Tokyo. This was during the time when Japan was going through massive waves of Westernization, particularly by the upper elite class. Members of the upper class, who had a strong penchant for Western cultures in general, enjoyed Western style desserts as a delicacy. Thus, being a Western style dessert, Christmas cakes were associated with the idea of Western modernity and social status. Therefore, it was a major hit when the Christmas cakes were commercialized and became more affordable to the general public. As Christmas in Japan developed as a full-fledged commercial event, competition among confectionery stores got intense. Different shapes and styles of Christmas cakes are released across the countless numbers of confectionery stores in the country; the cakes are no longer tied down to the traditional form of round white cakes with strawberries and Santa Claus on top. The Christmas cakes today are symbolized as a ritual of Christmas celebration; specifically, the act of sharing the cake with family or friends."
An excellent explanation of what's going on! I knew about fruitcake for Christmas, but these are totally different.
US pudding is called custard in the UK.
Now you'll be amazed what they think pants are.
Pudding however, now THAT is a weird Christmas tradition :)