When Prime Minister Lee Hsien Loong announced his new Cabinet line-up soon after last September's general election, he made it clear that planning for leadership succession was a key priority.
Younger ministers and new office-holders were given a range of responsibilities to expose them to new areas of work.
The key assignments given to Finance Minister Heng Swee Keat - such as chairing the Committee on the Future Economy - led some observers to conclude he was the clear frontrunner among the fourth-generation leadership.
So when Mr Heng suffered a stroke during a Cabinet meeting in May, undergoing emergency surgery the same day, many were worried that Singapore's leadership succession plans might be disrupted.
Then, two Sundays ago, Prime Minister Lee Hsien Loong caused hearts to pound when three hours into his televised National Day Rally speech - moments before he was to announce a recovered Mr Heng's return to Cabinet - he faltered on stage and had to take a break.
PM Lee rested for about an hour before returning to complete his address.
Announcing Mr Heng's return, and talking about leadership succession, he quipped: "After what happened, I think it's even more important that we talk about it now."
These episodes are reminders of the urgency of succession planning in Singapore.
Singapore is famous for its political model of identifying potential prime ministerial material far in advance. But even the best of plans can go awry, says law don and former Nominated MP Eugene Tan.
For this reason, Singaporeans should realise how important it is to have "sufficient breadth and depth in the Cabinet".
It was something PM Lee himself addressed after returning to the podium to complete his speech on the night of Aug 21. "We've now got the core team for the next generation in Cabinet. But ministers or not, all of us are mortal.
"Nothing that has happened has changed my timetable, or my resolve to press on with succession," he said, citing Chinese proverb sui yue bu liu ren, which means "time waits for no man".
With succession now more urgent than ever, Insight looks at the issues and options.
Countdown to next PM picks up speed
The plane is not just on the runway, it is picking up speed and getting ready for lift-off.
That is the stage Singapore's fourth-generation political leaders are at now.
Prime Minister Lee Hsien Loong has repeatedly said that he plans to step down some time after the next general election, which must be held by Jan 15, 2021.
6 men to watch
Since his entry to politics in 2011, Mr Chan has developed a reputation for quickly mastering his portfolios and his ability to connect with people on the ground.
Mr Chan's portfolios are significant ones, and complement his time in the Singapore Armed Forces, where he rose to the rank of major-general and was Chief of Army.
How the 2nd and 3rd PMs were chosen
Mr Goh was not his predecessor's first choice. The late Mr Lee had felt that Mr Goh had a tendency to try to please everybody, and could be awkward when addressing a crowd. But he refrained from naming a successor, citing the need for the next generation to choose their own man.
Besides, in his peers' eyes, Mr Goh was the man for the job. They had already decided this in 1984, and reaffirmed their choice in 1988, despite Mr Lee making his analysis of Mr Goh public in his National Day Rally speech that year.
Next PM will be picked by the young ministers
I am surprised by Mr Han Fook Kwang's article ("Relooking leadership renewal in Singapore", Aug 28).
He, of all people, should know that the process by which we choose prime ministers is anything but "opaque". He has worked on many books with Mr Lee Kuan Yew, and heard Mr Lee describe in detail leadership succession in the People's Action Party (PAP).
We scour the country to find able, honest and committed people to field in elections. Possible candidates go through a rigorous vetting process. This begins the day after every general election.