Barry Soetoro attended the Menteng One school in Jakarta, studied the Koran, and went to classes on Islam, despite the objections of his mother, Ann Dunham, a Catholic.
Barry moved there with his mother and his step-father when he was 6, and lived there for four years.
The teacher, Effendi, who taught at Menteng One for 29 years, remembers Obama as a "fat, curly-haired, curious boy".
Obama attended classes on Islam while the Christians attended classes on Christianity, said Effendi.
"His mother did not like him learning Islam, although his father was a Muslim. Sometimes she came to the school; she was angry with the religious teacher and said 'Why did you teach him the Koran?'" said Effendi.
"But he kept going to the classes because he was interested in Islam. He would also join the other pupils for Muslim prayers."