Every June 1, the Indonesian people commemorate the birthday of Pancasila. The Birthday of Pancasila was marked by a speech made by the first President of the Indonesian nation, Ir. Soekarno on June 1, 1945, at the Dokuritsu Junbi Cosakai (Independence Preparatory Investigative Agency) trial. In his speech, he presented the initial concept of Pancasila which became the basis of the Indonesian state.

Quoting from bpip.go.id, the history of Pancasila's birthday began with Japan's defeat in the pacific war, they then tried to win the hearts of the people by promising independence to Indonesia and forming an institution whose job it was to prepare for it. This institution is named Dokuritsu Junbi Cosakai. At its first session on May 29, 1945, which was held at the Chuo Sangi In Building (now the Pancasila Building), the members discussed the basic theme of the state. 

The trial lasted for almost 5 days, then on June 1, 1945, Soekarno conveyed his ideas and ideas regarding the basis of the Indonesian state, which was named "Pancasila". Panca means five, while sila means principal or principle. At that time Bung Karno mentioned five basic principles for the Indonesian state, namely the first principle of "nationality", the second principle of "Internationalism or Humanity'', the third principle of "Democracy", the fourth principle of "Social Justice", and the fifth principle of "Belief in One Supreme God".

After going through several trial processes, Pancasila was finally ratified at the PPKI Session on August 18, 1945. At that session, it was agreed that Pancasila was the legal basis of the Indonesian state.