Mr Chan Poh Meng's career in teaching came full circle when he retired from the education service while serving at his alma mater as its principal.

The 60-year-old concluded 35 years in service this year when he retired as principal of Raffles Institution, a position he had held since 2013.

Calling it a privilege, he said: "This is especially meaningful for me. I joined the school as a 13-year-old, graduated with my A levels, then started working as a teacher before finally coming home."

He was among 16 retiring principals who were applauded for their contributions to the education service at the 20th Appointment and Appreciation Ceremony for Principals at Shangri-La Hotel yesterday.

At the ceremony, 63 principals also received their appointment letters from director-general of education Wong Siew Hoong.

Mr Chan added that one of the biggest regrets of his education career was that by taking on more leadership challenges, he was pulled further away from the classroom, where he had found the biggest satisfaction as a teacher.

"I found myself spending far less time with the individual students in the classroom, which is impossible as a school leader. That is something which I miss a great deal."

Another retiring principal, Dr Hon Chiew Weng, 60, spent all 35 years of his career as an educator at Hwa Chong Institution (HCI).

For Dr Hon, the two most important milestones in his career were Chinese High School going independent in 1988 and the merger of Hwa Chong Junior College and Chinese High School in 2005 .

He had joined Chinese High School - currently the high school section of HCI - as a physics teacher in 1982.

In fact, he was Education Minister (Schools) Ng Chee Meng's teacher when the latter studied at Chinese High School.

Mr Ng, who was guest of honour at yesterday's event, said in his speech that Dr Hon used to make him do push-ups in class whenever he failed to answer any questions.

Dr Hon said with a laugh: "When he (Mr Ng) was promoted to be minister, I told my teachers 'never bully a student ah, you don't know when he's going to become your boss'."

In his speech, Mr Ng urged schools to grow the "Innovation Quotient" of students, through a 3Is formula - imagination, inquisitiveness and interconnections.

One of the principals appointed at the ceremony was Mrs Manokara Sugunavathi, 56, who will take charge of Cantonment Primary School.

The veteran educator, who has 33 1/2 years of service under her belt, was previously the principal of Jurong Primary School .

She said that the adoption of new ways of teaching aimed at fostering a sense of innovation in pupils will also have to depend on how parents embrace them.

She said that parents have been conventionally exposed to very academic-driven goals for a long time.

So they would worry about "whether their child will be prepared for the PSLE" when they see teachers veer off the standard methods of teaching.

"Changing parents' mindsets can be a challenge. It will take some time for more parents to see it," said Mrs Manokara, referring to the shift in teaching methods and approach.

She brought up the example of Scamper, a thinking tool implemented in her previous school Jurong Primary, which helped pupils think creatively.

Scamper - which stands for Substitute, Combine, Adapt, Magnify or minimise, Put to other use, Eliminate to an extent, and Reverse - guides pupils through a thinking process.

"We had to formalise a little structure so they (the pupils) knew where to bounce off their ideas."

For example, for a lesson on inventions, pupils would think about what they could invent that would be beneficial for Singapore.

"Innovation has to be contextualised. If not, there would be no value to the people we are offering it to," said Mrs Manokara.