Although punctuality is well attained in present Japan, many foreign engineers who arrived in Japan from the mid 19th century observed that Japanese were seemingly indifferent to the clock, which leads us to a question about the origin of punctuality in modern Japan. The present paper first explains the time system and clocks in the Edo period, and then follows the origin and the evolution of punctuality in various sectors of Japanese society. Introducing the historian Sakae Tsunoyama's two-layer theory to explain the origin of punctuality in modern Japan, the paper explores a question about when punctuality was attained and society accelerated in postwar Japan.
