ヂand ヅ - USAGE when ヂand ヅ are used? ぢand づ are said to be used in rendaku as well explained here below in other question. but when their equivalent sounds in katakana ヂand ヅ are used? redanku happens when the base word includes ち or づ, it turns into ぢand づ as in 鼻血 (はなぢ) nose blood that is composed of 鼻 and 血, and 血 is ち, becoming HANA+JI Ok! but I can write those words coming from romanji, but ヂand ヅ are not used in this case, so when ヂand ヅ are used?