Mr Tan Hwee Hock was 13 when his family was forced to evacuate their seven-bedroom, seafront bungalow in Pasir Panjang.
Evacuations were ordered as the Japanese advanced across Malaya during World War II, so the family moved into a two-room unit in Tiong Bahru.
It housed 20 people, including Mr Tan's six siblings and extended family.
Desperate for food and out of a job, Mr Tan's father, businessman Tan Thian Chye, turned the grass plot outside the ground floor unit into a garden where they grew tapioca, sweet potatoes and other vegetables.
For fertiliser, they used their own waste.
"Everything was precious. We had a urine pot in the house... we diluted it with water and used it as fertiliser," said Mr Tan. "To survive the war, we had to be inventive and resourceful."
When he was about 15, Mr Tan found work as a laboratory assistant at a medical college where the Japanese were studying metabolism.
He was paid $2.50 a day.
His Syonan Labour Department labour identity booklet, which logged his wages, is on display at the National Archives of Singapore's newly revamped World War II museum.
"After work at the end of each day, there would be a guard at the gate. You'd open a cloth bag and he would pour in a cigarette tin's worth of rice. This was more important than the salary," he said.
Mr Tan, who is now 87, recounted how godown labourers, carrying gunny sacks of rice, would cut slits in the packaging.
Young boys would run to gather the fallen grains.
"When I raised my children, I didn't let anyone leave one grain of rice on their plates," said Mr Tan, who has three children and six grandchildren.
After the war, the Tan family returned to their Pasir Panjang home.
It still stands today and is occupied by his 94-year-old sister.
Mr Tan, who went on to become a national breaststroke and water polo champion, dedicated much of his life to water sports as a lecturer, physical education specialist and coach.
Meanwhile, his gardening skills come in useful in his Jalan Layang Layang home in Bukit Batok where he maintains a small garden
This article was first published on February 10, 2017. Get a copy of The Straits Times or go to straitstimes.com for more stories.