万々一 まんまんいち Also written ばんばんいつ, 万万一 Meanings Adverb (if) by some very rare chance; in the very unlikely event that ... (more emphatic than 万一) See also: 万一 (まんいち). Kanji 万 ten thousand. Read as マン. 一 one. Read as イチ. Jinuma: Japanese Dictionary · Word lists