Post and Telecommunications Service Day (Hari Bakti Pos dan Telekomunikasi) is observed in Indonesia every September 27. This day commemorates the takeover of the post, telegraph, and telephone systems by Indonesian nationalists in 1945, shortly after Japan's surrender during World War II. The history of postal and telecommunications services in Indonesia dates back to the colonial era, with the first post office established in Batavia (now Jakarta) in 1746 and the first telegraph line inaugurated in 1856. The Dutch Colonial Government created a unified agency, PTT, in 1906 to manage these services. Following Indonesia's independence, the government nationalized PTT, which was later split into separate postal and telecommunications companies. Although this day is significant in the history of Indonesian communication, neither Pos Indonesia nor Telkom considers it their foundation anniversary, as they celebrate their respective anniversaries on August 26 and July 6.