Twenty-two letters written by Netaji Subhas Chandra Bose, mostly between 1921 and 1934, will be on display at the memorial at his birthplace in Cuttack from Sunday.
The West Bengal Archaeology Department found the letters in two bundles while cleaning his ancestral house in Cuttack, Janakinath Bhavan.
"We found the letters before the museum was opened to the public last year," said B K Rath, superintendent of the department and honorary director of the museum.
The letters do not have much political content except in one dated December 17, 1921. This was written from the Presidency Jail in Kolkata (then Calcutta) where he declared, 'I am confident that swaraj is at hand.'
Netaji's father Janakinath Bose received most of the letters at his residences in Cuttack or Calcutta after they were scrutinised and stamped by intelligence sleuths.
Anxious about his father's health, Netaji wrote from the Mandalay Jail in Myanmar on April 3, 1926: 'I was anxious to learn from mejdada's (his brother Sudhir Chandra Bose) letter that you were not doing well. Please let me know how you are now.'
The leader's faith in the divinity was also reflected in a letter -- written in Bengali to his mother Prabhabati Devi -- where he scribbled on top: 'Shri Shri Durga Sahay.'
Concern about his health came to the fore in almost every letter.
'You need not be anxious at all about my health. Will you be going to Kurseong (a town in West Bengal) for a change?" he wrote in another letter from Mandalay in 1926.
