The Trishaw rider Story
His story began in 1934 when he arrived in Singapore from Fujian province in China at the age of 22. Like many of his kinsmen from the Hock Chia dialect group, he became a rickshaw puller.
In 1937, a Peranakan housewife, Madam Chua Jim Neo, got him to start taking her four sons and daughter to school by rickshaw. Mr Lee Kuan Yew was her eldest.
Said Mr Lee's youngest brother, Dr Lee Suan Yew: "Imagine that, one man pulling at least four of us at one go. You have to be very strong to do that."
Mr Koh also put his green thumb to work, growing sweet potatoes and cucumbers in the Lees' backyard at Norfolk Road, in the Farrer Park area, where they lived until 1942. "Teong Koo also taught me how to rear chickens and ducks," recalled Dr Lee.
But to the Lees, Mr Koh is best remembered for taking care of Mr Lee when it mattered the most - when the Japanese invaded Singapore in 1942.
By then, the family had moved to their grandfather's home in Telok Kurau, farther from the city, to avoid getting hit by bombs.
One day, Mr Lee, then 19, and Mr Koh were checking their food stocks at the Norfolk Road house when they were ordered by the Japanese to go to a registration centre at Jalan Besar stadium.
They were to be screened by Japanese soldiers, who would decide if they were "cleared" to return home, or if they should be rounded up and taken away. Those who refused to be screened would be punished by the Kempeitai, the Japanese military police.
It happened that Mr Koh's coolie-keng - the dormitory for rickshaw pullers - fell within the registration centre's perimeter which was enclosed by barbed wire.
It was an area with many Hock Chia immigrants and Mr Koh had a friend who let him and Mr Lee stay for a night at his home at 75 Maude Road.
The next day, Mr Lee tried to leave the centre through the exit point, but the Japanese soldier on duty told him to join a group of young Chinese gathered nearby.
Feeling instinctively that this was ominous, Mr Lee asked if he could collect his belongings first. The soldier gave permission and Mr Lee took off. He did not return.
Instead, he laid low with Mr Koh for another day and a half until a different soldier was on duty. This time, he was cleared to leave.
Mr Lee recalls that episode in his memoir, The Singapore Story. Had he not escaped, he would almost certainly have been taken to a beach near Changi prison and shot to death.
The Lees believe they have the rickshaw puller to thank for Mr Lee's narrow escape from Sook Ching, an exercise to punish the Chinese in Singapore for supporting China's war effort against the Japanese. It is estimated that Sook Ching claimed between 25,000 and 50,000 lives.
Dr Lee told The Sunday Times that when he visited his eldest brother recently, Mr Lee, now 90, could still recall the episode in detail.
Dr Lee said: "My son told him, 'If it weren't for Teong Koo, the history of Singapore would have turned out very differently!'"
Mr Lee laughed in response, said Dr Lee.
Retired factory worker Tan Ah Mok, 84, who lived in Maude Road after the war and knew Mr Koh, told The Sunday Times: "Mr Lee's mother was very happy that he came back alive. So she treated Teong Koo well."
Dr Lee believes Mr Koh looked out for the family because his mother first looked out for him. When he wanted to try his hand at entrepreneurship, it was Madam Chua who helped him with the money he needed to get started.