From an article written by Rey Langit:
I recently reminisced with Senator Rene Saguisag on the dark days of Martial Law on my program “Kasangga Mo Ang Langit” (6-7am) on DWIZ882 KHz.
To his recollection, Martial Law was declared not on September 21 but September 23. Except that former President Ferdinand Marcos, he explained, was a numerologist, and wanted a multiple of 7 so the declaration was officially made the 21st. “But to me,” he recalled, the 21st of September 1972 was just another day in the office.” ( Proclamation No.1081 which imposed martial law was dated 21 September 1972. – eds.)
Saguisag remembers he was in San Beda, monitoring the rally of Ke Pepe Diokno, Bal Pinguel and Charito Planas in Plaza Miranda on the 21st. Historians, he says, should correct the date and establish that nothing eventful except on paper really happened on the 21st.