She has decided to refuse any outside assistance, including food, until the junta opens talks with the opposition. Her decision, revealed this week by her husband in Oxford, echoes Mahatma Gandhi's hunger strikes in India during that country's struggle for independence. Because of her stature within Burma and throughout the world, the junta cannot ignore her.
It is a characteristic move by Ms Suu Kyi, 47, and paves the way for the ultimate showdown between herself and the army, which has massacred thousands of people to hold on to power. Her food will run out within a month, just as the junta's showcase National Convention begins to discuss a new constitution for Burma.
'It is a kind of Gandhian non-acceptance of favours from her captors as a form of action against the regime,' her husband, Michael Aris, said. He insists that after 41 months of being held incommunicado, she will not back down. 'She knows very well what she is doing. She has had a lot of time to think about this.'
Throughout her campaign for democratic freedom in Burma, Ms Suu Kyi has advocated non-violence and reasoned negotiations against the bullets, mass arrests and torture of the Burmese military. 'One of the tragedies of this country is that there is a brick wall between the army and the civilians, and neither understands the other,' she said in an interview four years ago. 'If (the army) refuses a dialogue, we will just keep calling for one, because it is the right thing to do.'
Ms Suu Kyi became involved in Burma's struggle for democracy by chance. When she received a phone call in March 1988 that her mother was seriously ill in Rangoon, she was living in Oxford with her husband, a Tibetologist at St Antony's college, and their two sons. She was an eccentric figure, who would cycle around Oxford with her dog in the basket of her bicycle. She had not lived in Burma for 28 years.
She returned to care for her mother, and several months later student demonstrations against the military began, leading to the bloodbath of September 1988 when all popular protest was crushed. By that time, Ms Suu Kyi had become the most popular rallying figure for the opposition, and her speeches were attracting half a million people in Rangoon.
But Ms Suu Kyi had always known that her fate might call her back to Burma. Her father was Aung San, the Burmese independence hero who negotiated the country's freedom from Britain, only to be assassinated by a poltical rival in 1947. She left Burma for India in 1960, when her mother was made Rangoon's ambassador to Delhi. But throughout her secondary school years in India and her university studies in Oxford, where she read politics, philosophy and economics, she could see that her country was languishing under the military dictatorship of General Ne Win, who mounted a coup in 1962.
When she married Mr Aris in 1972, she made him promise that if she ever felt the need to return to Rangoon, he would not stand in her way. When she did return in 1988, it was not long before protestingstudents began to seek her assistance, in the name of her revered father.
At first, she was reluctant to get involved, having been away for so long. But as the country descended into turmoil she relented, and gave her first public speech in Rangoon on 26 August 1988. Surrounded by the biggest crowd the city had seen since independence four decades before, Aung San Suu Kyi finally donned her father's mantle.
'People have been saying that I know nothing of Burmese politics,' she began. 'The trouble is, I know too much. My family knows better than any how devious Burmese politics can be. I could not, as my father's daughter, remain indifferent . . . this national crisis could, in fact, be called the second struggle for independence.'
Initially the military did not take her seriously, expecting her to return to her comfortable family life in Oxford. But it miscalculated. As the army shot protesters in cold blood on the streets of Rangoon, the feeling increased that she was being called to save her people.
On the afternoon of 19 September 1988, at the height of the bloodbath in Rangoon, she sat in the front room of her home, calmly but resolutely denouncing the military for 'spoiling everything'. The crack of rifle bullets outside was making everyone else in the room nervous, but she never once flinched. 'You can't pick up something and then drop it,' she said. 'You have to see it through.'
After the military crackdown, she was one of the co-founders of the National League for Democracy (NLD), which quickly became the most influential political party. The junta, which calls itself the State Law and Order Restoration Council (Slorc), was unable to stop her growing popularity, and put her under house arrest. Even without her, the NLD won an overwhelming majority in national elections in 1990, but so far Slorc has refused to recognise the results.
Earlier this year, under discreet pressure from its main aid donor, Japan, the junta announced a theoretical timetable for a return to civilian rule. At the same time it has released some, but not all, political prisoners.
Mr Aris has been allowed to visit his wife twice this year, after two years without contact. 'She has lost weight,' he said when he visited her in July. 'She doesn't go into the garden because they lie in wait to photograph her. She has little to eat, and only the books in the house to read. She is completely cut off.'
Her only visitor is an officer from the military intelligence service. But Mr Aris says his wife is prepared to take the issue to the very end. 'She is strong, and her resolve is undented.'
The junta is in a difficult position. The last time Ms Suu Kyi held a hunger strike, after her house arrest, it gave in to her demands after two weeks: she wanted guarantees that her student assistants would not be tortured in prison. This time she is asking for much more: for talks to open and to continue until a political solution is found.
Just as the British could not afford to let Gandhi starve himself to death in India, so Ms Suu Kyi has now calculated that Slorc will not allow her, a Nobel Peace Prize winner, to die. Burma and the world is watching.