"Iroha" is actually a Japanese poem that makes use of all the kana phonetic characters once and once only. The order of these syllables was often used to number things and was used as the "alphabetic" order until the Meiji Period. The gates and yagura of Himeji Castle are likewise named in the order of the syllables in this poem. The first line of the poem continues I Ro Ha Ni Ho He To. See how many of these gates I have pictures for. One of these days I need to capture them all appropriately.