It has been a priority for Prime Minister Lee Hsien Loong right from the start - the search for Singapore's next prime minister.
Ten years into his premiership, it remains his biggest challenge, say political observers. "That seems to be a particularly pressing issue for the Cabinet and for PM Lee," says National University of Singapore (NUS) political scientist Reuben Wong. "Right now, we don't have a clear candidate."
With the other two prime ministers before Mr Lee, potential successors emerged earlier in their tenure, he adds. When Singapore's first prime minister Lee Kuan Yew passed the baton to Mr Goh Chok Tong, the third leader, PM Lee, was already in the wings.
There is, however, a team of younger ministers in place, the nucleus of Singapore's fourth-generation leadership. And PM Lee has since the 2011 General Election been appointing them to key positions in his Cabinet. Education Minister Heng Swee Keat, 53, for example, has been given two of the biggest political jobs of recent years - organising the Our Singapore Conversation and chairing the committee coordinating the marking of Singapore's 50th year of independence next year.
In August last year, when PM Lee promoted another of these younger ministers, Mr Chan Chun Sing, 45, and announced other leadership changes, he was asked if he was closer to identifying his successor. He said it was not his call to make but for "the younger ministers in the team to work out among themselves whom they will support as their leader".
Political watchers say this situation is unusual in Singapore's context. Since the 1960s, the People's Action Party has, through a policy of self-renewal involving careful selection and elevation of ministers, ensured smooth and predictable political succession. That is "one of the country's greatest strengths", says former Nominated MP Siew Kum Hong.
But with Singapore having entered a new era of greater political contestation, questions have been raised about the viability of the PAP's method of inducting talent.
For Mr Siew, the system works when the party is able to draw in the right people, but he notes that there is a "significant weakness in the PAP's ability to recruit".
For years, it has "skewed towards" the military, the civil service, government-linked companies and unions in recruiting candidates, leading to a lack of diversity among its ranks, he says.
The PAP's longstanding method of anointing leaders - recruiting those of a high calibre, putting them through the paces as ministers - may also no longer work with an electorate that has greater expectations of politicians.
NUS sociologist Tan Ern Ser says: "It is no longer merely about being sharp and smart, but also someone who comes across as sincere, wise and authentic, able to connect with people, command their respect, has charisma, and who sees politics as a calling to serve the people."
Age is another factor making this task an urgent one. PM Lee has said he plans to hand over the reins by 2020. By then, the two deputy PMs, Mr Teo Chee Hean and Mr Tharman Shanmugaratnam, will be 66 and 63 respectively. "If they become the next prime minister, will that mean Singapore's fourth prime minister will be at the helm for only one term?" asks Associate Professor Wong.
PM Lee has also indicated his wish to reverse the age trend of Singapore prime ministers - Mr Lee Kuan Yew became PM at 35, Mr Goh at 49, and PM Lee at 52 - by getting a younger successor. If this were a firm criterion, even the two ministers touted as possible successors, Mr Heng, 53, and Mr Chan, 45, may be a tad old.
So is the next prime minister even in the Cabinet now?
Strategy consultant Devadas Krishnadas says: "(PM Lee) has a technically capable collection of candidates in his first and second ranks but are they made of the right political stuff? This is a hard question but the long-term fate of his party depends on the answer."