| It is suspected that this naming is originated from the fact that in a book on strategy, it is described that "a castle is called a maru because a small circular castle is most appropriate to defend". |
それは軍学書に「城は小円を善とすること、城取の習とぞ、此故に丸とは呼ぶ也」等に記されたことによるらしい。 |