This is an excerpt from "Tzu Chi," by Mark O'Neill, describing the biggest Buddhist welfare organization in the world. "At the Helm" describes the Abode of Still Thoughts in Hualien, Taiwan, the headquarters of Tzu Chi, and the lifestyle of Master Cheng Yen.

The Abode is both the headquarters of a global enterprise with 10 million members and annual turnover of hundreds of millions of US dollars and a community of 150 nuns seeking peace and enlightenment away from the greed and extravagance of the material world.

The title 'Still Thoughts' comes from the name Cheng Yen gave herself when she was studying Buddhist scriptures in Taitong, the town in southeast Taiwan where she lived before she came to Hualien.

After she arrived here in 1962, she adopted a Spartan lifestyle for herself and her disciples, which has not changed in the 45 years since – a 17-hour work day, sleeping no more than five hours a night, a strict vegetarian diet and no holidays.

In the Abode, where she lives and works with the nuns, the waking gong sounds each morning at 0350. From 0420 until 0520, the nuns recite sutras in the temple in front of the three statues, followed by ten minutes of meditation and a 30-minute religious lecture by Cheng Yen. They eat a simple breakfast at 0600. It is only at this moment that she has anything like her own time.

At 0650, she holds a meeting with about 70 volunteers, from Taiwan and elsewhere in the world, in a meeting room next to the temple. They sit cross-legged on brown leather seats on the polished wooden floor, while she faces them, seated at a table with flowers. The room has wooden walls, with vases of flowers, religious paintings on the wall and a small white statue of the Buddha at the back. It has ceiling fans to keep the air cool. Cheng Yen gives an address of about 15 minutes. The room has television screens, which enable her to speak to doctors, nurses, patients and volunteers at Tzu Chi hospitals around the island. They report to her on operations and treatments and the stories of patients, happy and sad, which they have witnessed. The meeting is also an opportunity for the visitors and invited guests to give testimony and reports and for her to show video footage of the foundation's projects around the world. The meetings are carefully scripted and conducted with the slickness of a US news show. For visiting members, this face-to-face meeting with their master is the high point of their journey.

The room is too small to accommodate all the visitors. Others, less fortunate, sit in three nearby rooms and watch the presentation on a large television screen. Her television station, Da Ai (Great Love), records the morning address and broadcasts it, with sub-titles in Chinese and English, round the world in the evening of the same day. The address, Renjian Puti (Living Buddha), is re-broadcast four more times over the next 24 hours. It is the main link between her and her followers around the world.

After the meeting, Cheng Yen begins a day like that of a chief executive of a multinational. She receives a flood of visitors – her own disciples who report on Tzu Chi projects: doctors and other medical professionals, local and foreign, who speak about their work and their plans for the future: religious people, including Buddhist, Christian and Moslem, with whom she compares notes about their faith and how to put it into action: scholars and professionals, with whom she discusses ideas and projects. She plays close attention to the news, especially of natural disasters, and hears reports from her members in the countries affected. They decide together whether and how Tzu Chi should assist the victims. Most of the visitors come from the 26,000 Tzu Chi commissioners, the full-time managers of her global enterprise who report to her on ongoing projects and future plans, at home and abroad.

She avoids foreign dignitaries and journalists, unless they have a particular connection to Tzu Chi, like the presidents of El Salvador, Honduras and Nicaragua who came in person to thank her for building homes and schools and distributing food and clothing to victims of disaster in their countries. Since the Foreign Ministry is proud of Tzu Chi, it sends foreign dignitaries to Hualien to see it. She leaves it to her colleagues to receive them. As Tzu Chi expands in the world and takes on more members and projects, so her workload becomes heavier. There are ever more projects to be discussed and more decisions to be taken.

She does not have an office of her own but shares a workroom with her colleagues, with a constant flow of people coming in and out. She prefers this collective atmosphere to the formality of a large executive office with heavy furniture and corporate secrecy.

During the meetings, she is surrounded by a team of people. There are secretaries, staff members from the departments concerned, an interpreter if it is a foreign visitor and chroniclers who record everything she says. They publish excerpts of her words in the foundation's monthly magazine and 500-page books which appear four times a year, describing her life during the previous quarter. Not everything is published – personnel matters and plans that are not yet mature are written in internal documents that are shown only to staff. Television cameras are another part of the scenery – excerpts from the meetings are broadcast on the foundation's channel, to let the members know what Cheng Yen is doing.

At midday, she enters the Abode's canteen for a lunch with her disciples and visitors. She sits at the head table with senior colleagues and invited guests. At the other tables sit the 150 nuns who belong to the community and Tzu Chi members from outside. The food is strictly vegetarian, with no milk or dairy products. Cheng Yen eats little and leaves after several minutes.

Unlike many in Taiwan, she does not take a nap after lunch, saying that she has no such habit. She drives herself hard, forcing herself to overcome fatigue and sickness. "A body that knows no exhaustion and a mind that knows only determination belong to a person's superior self. When the inferior self is forgotten and the superior self takes over, then a person can gain super energy and force himself to go on."

The hectic schedule of meetings continues until 1800, after which she does not receive visitors. Eating dinner takes only a few minutes. With the time her own, she reads newspapers and e-mails, surfs the Net and watches television, both her own station and some of Taiwan's 80 other channels, to keep abreast of local and global events. One of her favourite programmes, on her own station, is the evening drama at 2000. This is based on the life of one of her disciples, whom she selects as outstanding and the drama department of the Great Love station turns into a multi-part series.

She also telephones members on foreign assignments, to check on the state of the mission, verify their personal safety and discuss what more needs to be done. If she decides Tzu Chi should help the victims of a disaster, she calls a meeting, to be attended by officials from the humanitarian aid department and the nuns responsible for researching the country involved. They will contact members in the country affected or, if they are none, in the country that is nearest and decide what action to take. Like the office of a multinational chief executive, hers is equipped with video link-ups, computers, mobile telephones and all the trappings of international telecommunications. She can call a meeting at any time of the day or night and her staff are on call 24 hours a day.

This intense schedule is only interrupted by visits to Tzu Chi institutions in Hualien, including its large hospital, university and primary and secondary schools. She will visit individual patients, meet doctors and nurses and give prizes to school and university students. She pays special attention to long-term patients and those with severe injuries. When new doctors and nurses come to work at the hospital, she officiates at a ceremony where they swear to uphold its code of practice, to treat all patients equally, regardless of race, gender, skin colour or social status. At Chinese New Year, she attends events to mark the festival, giving out red packets to thank people for their hard work during the year. For anniversaries, performances and special events, she attends ceremonies at Jing Si Tang (Hall of Pure Thoughts), the foundation's giant meeting hall in Hualien.

The lights in the Abode go out at 2140, although residents can stay up if they wish, to read or meditate with a small light. Cheng Yen goes to bed between 2200 and 2300, in a small, plain room. She lives with two white cats, one a Siamese, one an Angora, gifts to her in 2002. Like their master, both are vegetarian and do not even kill mice. They walk behind mice, following them but not too close, while the mice do not try to run away. One is called Shan Lai, which means the 'arrival of goodness', and the other Show Show, which means 'double charm'.