Film director Biyi Bandele first heard of the Nigerian book Half of a Yellow Sun while the author was still writing it. "I met Chimamanda Ngozi Adichie at a literary conference where she told me she was working on a book about the civil war in Nigeria and the fate of the Biafrans," Bandele says.
As a playwright and fellow Nigerian, Bandele was excited by the prospect of a novel dealing with the turbulent history of his country since independence in 1960 from British colonialism and the subsequent ethnic war resulting from a minority group establishing its own republic of Biafra.
"I read Half of a Yellow Sun as soon as it was published and was excited by what it contained," he says. "I knew there would be a film in it some day."
With a background in writing for the theatre and television and directing short films, Bandele set about the task of condensing the 450-page epic novel into a screenplay. The task took him and his producer Andrea Calderwood (The Last King of Scotland, the story of Ugandan dictator Idi Amin) six years to bring to the screen. The cast includes Twelve Years a Slave's Chiwetel Ejiofor as a Nigerian academic and Thandie Newton as his lover Olanna who decide to teach in a remote town in eastern Nigeria, home to the Igbo ethnic group to which they belong.
"Chiwetel has always been a friend of mine and right from the start had agreed to be in the film," Bandele says.
"After our filming he went straight on to 12 Years a Slave. Thandie Newton had come on to the project about three years into the process and I knew she would be ideal for one of the leading female roles."
Adichie's novel about the ethnic tensions that led to civil war and the Biafran crisis was written from several points of view, most notably that of the houseboy, an illiterate peasant who gets an education under the guidance of his middle-class master and mistress Odenigbo (Ejiofor) and Olanna.
In his screenplay Bandele tilts the focus to Olanna through whose eyes and reactions we see the unfolding of the war and its impact on the minority Igbo.
Determined to crush the ethnic rebellion, the majority Hausa, who had control of the north, sent in their troops to start a reign of terror.
The war played out between 1967 and 1970, ending in defeat for the Biafrans who were literally starved and bombed into surrender. It is an African scenario of ethnic genocide that would be played out a generation or two later in Rwanda.
Bandele defends his decision to present the story from the point of view of a young, middle-class woman by arguing adaptions of any epic novel are by their nature a distillation of the original characters and points of view.
"I don't think I've seen any film adaptation that doesn't work this way," he says. "People forget that the form of the novel and the form of the film simply don't get on."
In his production notes, Bandele explained that the key reason for making the film was so that his country's turbulent history would not be forgotten.
"Immediately after the war we had this flurry of literature about it - and then nothing. It just became the elephant in the room; nobody talked about it."
In the 40 years since the Biafran crisis, Nigeria, Africa's most populous country, has endured a series of military coups and counter-coups, each as bloody as the last. According to Bandele, Nigerians are still dealing with the ethnic tensions that precipitated the short-lived republic of Biafra.
"Like many middle-class Nigerians, Bandele experienced a British-style education and moved to England as a young man to further his writing and theatre career. "I felt there were better opportunities for me than in Nigeria."