It’s interesting to see the different symbol designs for flags of Japanese towns and cities. Most show the same clean and uncluttered style from the Japanese flag.
Sendai, Miyagi (1933)
Kawasaki, Kanagawa (1925)
Hiroshima, Hiroshima (1896)
Kitami, Hokkaido (1947)
Kochi, Kochi (1920)
Naruto, Tokushima (1947)
From this list of Japanese municipal flags on Wikipedia (split into regions).
A few designs are briefly explained over on Pink Tentacle.
Biei’s symbol, for example, features the hiragana び (bi) in the shape of Mt. Tokachi.
Via Design Observer.