Since last April, I've been spending my weekdays in Hikone, a city of Shiga Prefecture located by Lake Biwa. One day, while driving to my university, I was surprised to find four black swans in the outer moat of Hikone Castle.
These black swans, having red beaks with white at the tip, are identical in size and shape to white swans that live in the same moat, except in the color of their contour feathers. I asked why at the Tourist Bureau of the Hikone Municipal Government, and how those black swans had come to live in the castle's outer moat. Here is what I learned:
On March 3, 1860, Naosuke Ii, ruler of the Hikone Han (domain) as well as a "great elder" of the Tokugawa Shogunagte, was assassinated by soldiers who had defected from the Mito Han, outside the Sakurada Gate of Shogun's castle in Edo, now Tokyo.