Жапон тілінің ежелгі панграмма ақыны – Ироха

Early Middle Japanese pangram poem, composed before 1079 in the Heian period

The Iroha (いろは) is a Japanese poem. Originally the poem was attributed to Kūkai, the founder of Shingon Buddhism, but more modern research has found the date of composition to be later in the Heian period (794–1179). The first record of its existence dates from 1079. It is famous because it is a perfect pangram, containing each character of the Japanese syllabary exactly once. Because of this, it is also used as an ordering for the syllabary, in the same way as the A, B, C, D sequence of the Latin alphabet.

The Iroha contains every kana only once, with the exception of ん ( n), which was not distinguished from む mu in writing until the early 20th century (see Japanese script reform). For this reason, the poem was frequently used as an ordering of the kana until the Meiji era reforms in the 19th century. Around 1890, with the publication of the Wakun no Shiori (和訓栞) and Genkai (言海) dictionaries, the gojūon (五十音, literally "fifty sounds") ordering system, which is based on Sanskrit, became more common. It begins with a, i, u, e, o then ka, ki, ku and so on for each kana used in Japanese. Although the earliest known copy of the gojūon predated the Iroha, gojūon was considered too scholarly and had not been widely used. Even after widespread use of gojūon in education and dictionaries, the Iroha sequence was commonly used as a system of showing order, similarly to a, b, c in English. For example, Imperial Japanese Navy submarines during the Second World War had official designations beginning with I (displacement 1,000 tonnes or more), Ro (500 to 999 tonnes), and Ha (less than 500 tonnes). Also, Japanese tanks had official designations partly using Iroha ordering, such as Chi ha (ha meaning the third model). Other examples include subsection ordering in documents, seat numbering in theaters, and showing go moves in diagrams (kifu).