When Chew Gek Khim first joined the family business, she didn't know how to read accounts.

But she told herself: "Okay, never mind, I have to do it. There are 52 weeks in a year. So every weekend, I will read one annual report. After one year, I would have read 52, right? After two years, I would have read 104. And after four years, I would have read 208. At some point, it's going to get in, right?"

She laughs.

So you actually did that, I ask.

"Yah," she says. "I mean, in life, you just get on and do it. If you have the luxury of time, what's the big deal, right? So my attitude is, it's all practice. You might not be brilliant but you manage."

Lunch with Ms Chew, 56, is an interesting affair.

For one thing, she is among the very few women in Singapore heading a public-listed company, and for another, there's her family background.

She is executive chairman of The Straits Trading Company, which is part of the Tecity Group founded by her late grandfather Tan Chin Tuan, one of Singapore's pioneer bankers and chairman of OCBC Bank from 1966 to 1983.

Tecity, which she heads, also has an investment arm and oversees the philanthropic Tan Chin Tuan Foundation.

In the late noughties, Ms Chew made headlines when she wrested control of The Straits Trading Company from the Lees, another old-money family whose patriarch Lee Kong Chian was also a long-time OCBC chairman.

Despite the very public tussle, she has managed to maintain a low profile all these years.

We're having lunch at the Tan Chin Tuan Mansion, a two-storey colonial building with a modern 20-storey residential tower wing, owned by Mr Tan's family.

The white, conserved mansion is a landmark in Cairnhill Road and I have always wondered what it is like inside. Rumour has it that would-be tenants must first be interviewed and approved by Ms Chew. (More of that later.)

I arrive early and am met by two PR persons at the old building. A striking chandelier hangs from the second floor to the first, but the house is otherwise quietly furnished with classic dark sofas and gold-brown drapes.

What catches the eye are the walls. They are curated with photos of Mr Tan, complete with captions like in a museum. A bust of the patriarch, who died in 2005 at the age of 98, sits on a cabinet.

Ms Chew arrives, driven in a black Lexus. She is petite, very slender and spots a black, shiny bob and delicate eyebrows.

She's in her trademark cheongsam and wears black high-heeled pumps, the brand of which I can't discern, and carries a white handbag which is logo-less. The only jewellery are discreet earrings which look to be diamond and jade.

In our two-hour lunch, she comes across as no-nonsense and practical, but there is also a more relaxed side. She laughs easily and rather loudly, and is a good storyteller.

The PR people suggest she give us a tour of the house. She is happy to do so and we spend the next 10 minutes peering at photos of Mr Tan while she narrates his life, before heading to the second floor.

A table has been set at what used to be a verandah overlooking a large garden. When the Central Expressway was built, a sizeable chunk of their land was acquired. Soundproof glass ensures you can't hear the busy traffic outside.

Lunch is prawn noodle soup, ngoh hiang and fruit. Each table setting comes with both a napkin and a bib. It's the first time I've encountered a bib.

"You can choose to use either one," she says, reaching for her bib. It is in dark blue cotton with an embroidered flower. "It's good when you want to eat things like mee siam or laksa."

The PR person joining us for the meal puts on his bib. I decide to wear mine, too.

OUR lunch takes place soon after Prime Minister Lee Hsien Loong's New Year's Day message in which he said that in 2019, Singapore will mark the 200th anniversary of Stamford Raffles' 1819 landing. Among other things, the bicentennial will remember the country's forefathers .

Ms Chew is cheered by this news because she feels strongly that young Singaporeans should know more about the country's past, including its corporate history.

She points out that when the British started pulling out of Singapore after World War II, a lot of shares in the companies they started were put up for sale.

At OCBC, her grandfather acquired for the group colonial-era companies like Raffles Hotel, Robinsons and also Straits Trading, which was started in 1887 by a German and a Scotsman to smelt tin.

"He was instrumental in buying up these shares and the primary reason behind it, apart from wanting to take control, was a little bit of national pride," she says.

"People of his generation were proud for businessmen to leave an Asian mark, to say that we Asians can also run these companies."

In 2000, banks in Singapore were directed to divest non-banking assets and OCBC started selling off these companies.

Mr Tan's family had a lot of shares in Straits Trading. Through them, Ms Chew gained control of the company. Under her, Straits Trading, which marks its 130th anniversary this year, has diversified into areas like real estate and hospitality. She was named Businessman of the Year 2014 for turning a staid holder of low-yielding, hard-to-sell assets into a vibrant investment firm with diverse interests in the region.

Her grandfather clearly had a big impact on her and we spend much of lunch talking about his influence.

Her mother is the second of Mr Tan's three children. Ms Chew grew up in the mansion with her family and grandparents, and now lives in one of the 18 units in the apartment block.

"I've hardly ever left home," she says. "I'm constant. The house is constant... I'm the one who feels the most attachment to this place."

Her parents, both doctors in their 80s, also live in a unit there. Her younger sister and brother used to do so but recently moved out.

She studied at Singapore Chinese Girls' School down the road, chosen for its proximity to home. "Because of the racial riots, the advice was to put your daughter in a school that's nearest so that if ever there are riots, you can just go home."

Family life was loud and colourful. "Grandfather was hard of hearing, so everybody was allowed to scream."

Clearly, grandfather and granddaughter "got" each other.

She recounts how her parents and siblings once went on holiday, leaving her with her grandparents.

She was in university then and wanted to go with friends to the wholesale fish market in the early morning.

When her grandmother asked her what time she was coming home, she said "tomorrow".

"Wow, she blew up. I mean, you can imagine, 1970s decent young girls don't tell their grandma, 'I'm coming home tomorrow.' And then there was my poor grandfather trying to stay out of it."

When her grandmother pressed him to say something, all he said was, "Leave the lights on for her".

"She got very angry and he looked at her very calmly and he said, 'Look, she's 18. When you were 18, you were married to me. She must know what she's doing. Leave her alone.' Wow, you're a friend for life."

Another time, a friend persuaded her to shop for jeans. "I turned up in jeans. My grandfather looked at my jeans and he pulled me aside and said, 'Khim, if your mum doesn't give you enough pocket money, I can supplement you, you know. You don't need to wear this kind of cloth. You can wear silk and velvet or something else.'"

I wonder if she got a big allowance, given her wealth.

"My mum was extremely strict, so no. But having said that, I didn't really need a big allowance. You have everything, you know, you don't need to really buy anything."

The richest part of her childhood were actually the experiences, she says. Her grandfather knew many people including Malcolm MacDonald, former British Commissioner-General for South-east Asia, who was a house guest, and she met David Marshall. "When you're growing up, these are just names, but later on you realise the historical significance."

She says she was a mediocre but conscientious student. She loved the Girl Guides and made lifelong friends there, and was a librarian. She went on to National Junior College, then did law at the National University of Singapore, and spent three years at Drew & Napier.

She left because of the "internal politicking" and decided to take up her grandfather's offer to join the family business. Looking back, she believes he was impressed by the "condition" she set him.

"My condition was very simple. I said, 'We get along very well as grandfather, granddaughter. I'm not sure we can work together. You might not like me, I might not like you, we might have very different styles. So how about I give it two years and if it doesn't work, I'll quit, no hard feelings.' He said, 'Okay.' And that was my only condition.

"I didn't think much of it then, but it seemed a very sensible thing to say to him, right? I live in your home, I get along well with you, why on earth do I want to ruin my relationship? But in hindsight, maybe that's what impressed him.

"I didn't talk about pay. I didn't talk about leave."

He threw her into the deep end and she helped structure his various businesses. "His attitude in life was, 'If you're not stupid, you can jolly well learn. And if you have money, you can hire people. So what's wrong with you? There is nothing that cannot be solved.'"

When he wanted to build the apartment block in Cairnhill, she oversaw the construction and even checked out the unfinished 20th floor wearing "yucky boots".

As to whether tenants - there are currently 13 families - are interviewed, she says they are, but she gets someone to do it and "it's actually not that strict".

It's not an uncommon practice elsewhere, she points out, and it's meant to ensure a neighbourly environment where people aren't "throwing wild parties at 2am and getting upset with each other".

Heading the family business was "highly accidental", she says,"but I think in life things just happen, you go along and you do what you have to do".

She makes no apologies for her privileged background and how it has helped her be where she is. She borrows a line from Twelfth Night and says it was "thrust upon me".

Her siblings are involved in the business but not other family members. She and her family are listed as No. 23 in Forbes' 2017 list of richest people in Singapore, with a net worth of US$1.4 billion (S$1.85 billion).

Having Mr Tan as her grandfather gave her two specific advantages, she says. One was how people were less inclined to bully her. "The second advantage is that you have the luxury of not needing the job. My attitude is that if you're going to give me a lot of nonsense, I can walk out, you know, I don't need this job. So I'm doing it because I like it."

She clearly loves the thrill of business and is most animated talking about it. Of her private life, she'd only share that her husband is in education and they have a son and daughter,

I ask what she wants to be remembered for and she says nothing in particular, but "I want to feel my life wasn't a waste".

"You don't want to say she lived and died and she did nothing, right? I used to joke, 'What does your epitaph say? She had beautiful skin and afternoon tea?' I do not want that."

As we make our way downstairs after lunch, she mentions how she's not a foodie and I remark how slim she is. "Yes, I'm a lightweight," she laughs, then adds, "But I hope not metaphorically."

That, she can be assured, she is not.

Twitter @STsumikotan