"I made up lots of characters and little events, but I have tried to be as accurate as I can about the details of the camp," Mr Hill said.
He said the former World War I military training camp became the first prisoner-of-war camp for the Japanese in the British Empire.
The first prisoners were Japanese civilians and "they basically accepted they were prisoners" and caused no trouble.
When the first Japanese soldiers and armed forces began arriving at the camp however, it was only a matter of time before confrontations between them and New Zealand authorities began.
"Some Japanese officers tried to improve relations, to make sure the two sides could exist together in the camp," Mr Hill said.
It was arranged that some New Zealanders would learn the Japanese language, to "show they respected Japanese culture and the Japanese way of thinking".
The idea was if prisoners felt they were being treated with respect, they might not cause trouble.
Young Ewen and his friends start frequenting the camp for Japanese lessons and ultimately a friendship blossoms with their Japanese teacher, who ends up being the first man shot in the riot.
Mr Hill said writing for a younger demographic allowed him to revisit his own youth.
To develop Ewen's character, he thought back to what he was like when he was 13, what his son was like, and what his grandsons are like now.
He said he enjoyed writing for that age group "because they're coming across ideas and experiences for the first time".
"They're surprisingly sophisticated, they have a good vocabulary and understand a lot.
"They're a lovely mixture between naivety and sophistication."
Mr Hill said former journalist Mike Nicolaidi's book, The Featherston Chronicles, was one of his key sources while writing the novel.
While Mr Hill, a New Plymouth resident, has no ties with Wairarapa, he visited Featherston while researching for Enemy Camp.
"I felt it was only appropriate that I came down and got it as close to the facts as possible."
He spent time driving through the streets, making sure he got building placements and road junctions right, and spoke to various people in the area.
"If I got anything wrong it's my fault and I apologise profusely," he said.
Mr Hill has written a number of novels set during various wars.
"War is wonderful to write about because it involves conflict - physical, mental and internal."
Enemy Camp will be available in bookstores from early March.
