For more than a century and a half, the former Keng Teck Whay building in Telok Ayer Street was closed to the outside world.
The building, now used by the Taoist Mission (Singapore) and often mistaken for the more famous Thian Hock Keng Temple next door, was - from around the 1850s to 2010 - home to a private mutual aid Hokkien Peranakan organisation, reserved exclusively for its 36 founding members and their male descendants.
This brotherhood of Chinese merchants and traders, known as the Keng Teck Whay, was founded in 1831 and is the earliest of its kind here.
Within the building's walls, members worshipped the Sanguan Dadi (Three Emperor-Officials), venerated their ancestors and held meetings - originally in a mix of Hokkien and Malay - to discuss how to offer financial and bereavement support to members and their families.
The building was acquired by the Taoist Mission in 2010. Keng Teck Whay relocated to its premises on Changi Lorong 104 after it was unable to afford restoration works when the building was gazetted as a national monument in 2009.
Following a $3.8 million restoration project, the building officially reopened in 2015 as Singapore Yu Huang Gong (Temple of the Heavenly Jade Emperor), in honour of the highest deity in Taoism. The temple is open to the public.
You could imagine some of the very important people who used to walk about there; you felt you were walking in their footsteps.
KENG TECK WHAY SECRETARY AND ARCHIVIST RONNEY TAN, on the founding members of the association.
Taoist Master Lee Zhiwang, president of the Taoist Mission, said the building is steeped in history. "This temple already comes with a ling qi (aura), or in modern terms, a kind of magnetism. A newly built temple just can't compare."
Before the Societies Ordinance was passed in 1889, Keng Teck Whay was classified as a "secret society". While the number 36 was associated with triads whose members took 36 oaths during their initiation rites, Keng Teck Whay secretary and archivist Ronney Tan, 63, maintains there was nothing sinister about the way the society was run during his time.
"We talked about very mundane stuff," said Mr Tan in the same back hall where he accompanied his late father to regular committee meetings from 1980 onwards. There were also about five annual veneration ceremonies for the Sanguan Dadi and their ancestors.
Mr Tan added: "It wasn't like the old days. In the past, they did business, so they always had meetings here. Although we still consider ourselves a brotherhood, we don't have so many meetings because most of us have less free time."
Most of the founding members could trace their ancestry to Zhangzhou in Fujian province, China. Their surnames were Ang, Chan, Chee, Cheong, Chia, Chua, Gan, Ho, Khoo, Koh, Lee, Neo, Ong, Seet, So, Tan, Tay, Yap and Yeo.
Many were connected to prominent members of the community here. Tan You Long was Tan Tock Seng's elder brother; Chia Poh Eng was the father of Chia Ann Siang. Yeo Kim Swee and Seet Boon Tiong were prominent merchants. "You could imagine some of the very important people who used to walk about there; you felt you were walking in their footsteps," Mr Tan said.
At the beginning, they each contributed 100 Spanish dollars to the association's central fund. Sixteen of them also helped fund construction of Thian Hock Keng Temple next door.
About 15 of the lineages have already disappeared, Mr Tan said. There are now about 35 members, 17 of whom live in Singapore, and they range in age from 26 to 88.
The male-only tradition is unlikely to change any time soon, he said.
The building was constructed in traditional Hokkien style, featuring curved roof ridges with upturned "swallow-tail" ends. The roofs are adorned with dragons, fish and flowers made using a jian nian (cut and paste) technique where ceramic bowls are cut into smaller pieces and combined to form intricate designs. Some of the dragons are intended as symbols to ward off fire.
The front hall, lined with floor tiles imported from England, contains more than 80 statues of deities, including the Sanguan Dadi. There is also a more than 3m-high statue of Lao Tzu at the entrance.
Near the ceiling are illustrations painted by craftsmen from Quanzhou, Fujian province, during the restoration process. The illustrations in the front hall depict scenes from The Twenty-Four Filial Exemplars, a classic text on Confucian filial piety written in the Yuan dynasty.
A two-storey back hall contains a stone ancestral tablet inscribed with the names of 35 of Keng Teck Whay's founding members.
Markedly absent is the name of one member who was expelled in disgrace - and all his descendants banned - after marrying the widow of a fellow founding member.
Mr Tan thought about reinstating the name, but Master Lee advised him against it. Said Master Lee: "You have to respect their decision. In Chinese thinking, we believe you can't take a brother's wife. At that time, it was seen as a huge offence."
And behind the entrance gateway is an octagonal pagoda rising above a square hall - evoking the idea of Tian Yuan Di Fang (round heaven and square earth) in ancient Chinese geographical thought, the round heaven and square earth symbolising yang and yin respectively.
The pagoda's second level houses the Yuhuang Shangdi (Heavenly Jade Emperor) and Siyu (Four Heavenly Ministers), while the topmost floor, accessed via a step ladder, contains statues of San Qing Dao Zu (Three Pure Ones).
A red spiral staircase winds its way up to the pagoda that was used for paying respects to the Heavenly Jade Emperor - even though there was no statue of the deity there in the past - and was previously forbidden to women.
Mr Tan, who has been up there only four times, said: "They say that in the late 1970s, a woman once went up there when she was having her period, and for half an hour they couldn't get a (divine answer) with the poe."
Poe, or moon blocks, are wooden crescent-shaped divination tools thrown to request an answer from the deities. A divine answer, signifying "yes", happens when one falls with its flat side up, and the other, with its round side up.
Even today, the pagoda is open to the public just 17 times a year. This is for safety reasons due to the age of the building and to respect the sanctity of the space .
"You need to go up with sincerity, not by treating it as a (tourist) attraction," said Master Lee.
There are exceptions. "In 2015, when we opened, a lot of Thais came to make offerings," said Master Lee. "They told us they dreamt about the Heavenly Jade Emperor. Looking around, they couldn't find the deity from their dreams, so I took them upstairs."
The building bears traces of a long history. But structurally, it remains more or less the same - save for a door in the back hall added a few years ago for fire safety reasons, and an additional back portion housing a toilet acquired by the Government around the 1950s.
"It's like returning to an old home," Mr Tan said.