Koka finally has an English Web site:
http://www.city.koka.shiga.jp/english/index.html

It’s not bad. However, one common error is “Koka City.” It should just be “Koka.” If you say “Koka City,” it means “City” is part of the city’s name. The city’s name is “Koka,” not “Koka City” (=甲賀シティ市).

For example, in the US, we have “Kansas City” and “New York City.” In both cases, “City” is part of the city’s name.

In Japan, we don’t have any city names where “City” is part of the name. We can say “city of Koka.” And for Japanese cities whose name is the same as the prefecture, we can say for example, Niigata city, Saitama city, etc., to avoid confusionwith the prefecture’s name. In such cases, “city” should not be capitalized.