Sim Woh Kum

In the aftermath of the case, both Mimi Wong and Sim Woh Kum were considered to be the first couple to be sentenced to death and executed in Singapore since its independence. Simultaneously, Wong was also the first woman to be subjected to capital punishment in Singapore since its independence from both British colonial rule and Malaysia. Her case gained notoriety since its occurrence, and it was considered to be one of the most shocking murder cases which Singapore had faced in its years as an independent nation. In July 2015, more than 45 years after the murder of Ayako Watanabe, Singapore's national daily newspaper The Straits Times published an e-book titled Guilty As Charged: 25 Crimes That Have Shaken Singapore Since 1965, which included the case of Mimi Wong as one of the top 25 crimes that shocked the nation since its independence in 1965. The book was borne out of collaboration between the Singapore Police Force and the newspaper itself. The e-book was edited by ST News Associate editor Abdul Hafiz bin Abdul Samad. The paperback edition of the book was published and first hit bookshelves in June 2017. The paperback edition first entered the ST bestseller list on 8 August 2017, a month after publication.

Singaporean crime show True Files re-enacted the trial of both Sim Woh Kum and Mimi Wong, and the re-enactment first aired as the second episode of the show's first season on 30 April 2002. The episode is currently viewable via meWATCH (previously named Toggle) since 5 February 2016. Wong was portrayed by Singaporean actress Eve Ooi, while Sim was portrayed by Singaporean actor Tommy Tan. The case was also re-enacted in crime show Whispers of the Dead, which also re-enact the notable cases solved by forensic pathologist Chao Tzee Cheng; the episode was aired in 2014 as the second episode of the show's first season. In this re-enactment, the identities of the people involved were changed to protect their identities. For example, Wong was renamed as Suzie Tay, while Sim was renamed as Lau Teck Seng, and the victim Ayako Watanabe was renamed as Aika Nakamura in this re-enactment.

Sim Woh Kum (冼松锦 xiǎn sōngjǐn; c. 1933 – 27 July 1973), also spelt Sim Wor Kum, was a Singaporean who was best known to be the accomplice of Mimi Wong, a bar hostess who was the first woman to be sentenced to death for murder in Singapore since its independence. Both Sim and Wong were alleged to have murdered Ayako Watanabe, who was the wife of Wong's Japanese lover on 6 January 1970. Sim had also helped Wong to restrain the victim while Wong repeatedly stabbed the woman to death. Both Sim and his wife were executed on 27 July 1973, making them the first couple to be subjected to capital punishment in Singapore since its independence in 1965.

On 27 July 1973, nearly three years and seven months after murdering Ayako Watanabe, 40-year-old Sim Woh Kum and his wife Mimi Wong, then 34 years old, were both hanged at dawn, with executioner Darshan Singh carrying out the executions. On the same day of the couple's joint executions, another convicted murderer, Osman bin Ali, a gardener who killed a cook and an amah in Leedon Park in November 1970, was executed at around the same time as Wong and Sim's executions.

In January 1970, Mimi Wong went back to her estranged husband Sim Woh Kum, then aged 37, to tell her about her plans to kill a Japanese woman. Wong even offered Sim some money if he could help her to do the job. Despite his own reservations about committing murder, Sim decided to accept the offer for he still loved Wong and he was facing huge financial troubles while alone taking care of his mother and two sons.

On 6 January 1970, Wong and Hiroshi shared a dinner at their Everitt Road house. Upon knowing that Hiroshi was working overtime that night, Mimi Wong knew that she could take the chance to execute her plan.

In November 1970, the trial of Mimi Wong and Sim Woh Kum began to take place.

After a trial lasting 26 days, on 7 December 1970, High Court judge Tan Ah Tah pronounced the verdict in court. Wong and Sim were found guilty of murder and sentenced to death for murdering Ayako Watanabe. The two judges, Tan Ah Tah and Choor Singh, found that Wong was indeed in control of her mental faculties and thus was not mentally abnormal at the time of her crime, and had intended to murder Ayako out of jealousy over the possible break-up Hiroshi would initiate with her. As for Sim, the judges felt that he should take full responsibility of committing the murder since he shared the common intention with Wong to do the act, hence they sentenced him to death together with Wong.

Not only that, Sim was addicted to gambling, and he always gambled away the couple's hard-earned money, which aggravated the family's already-precarious financial situation. Sim was later fired from his job because of this habit, and the family's life savings were subsequently spent away. This forced Wong having to go take up part-time jobs to support their family, including a stint at a bar as a hostess. Despite his loss of employment, Sim continued to gamble, and he sometimes stole Wong's hard-earned income to gamble. Given their financial difficulties and Sim's own incompetence, Wong was slowly becoming disillusioned with Sim, and she thus left him in 1963.

In 1956, at a picnic, Sim, then 23 years old, first met Wong Weng Siu, a 17-year-old woman was invited to the picnic by a friend. Subsequently, both Wong and Sim became romantically involved. The couple dated for the next two years before they married in 1958. The couple went on to have two sons, one in 1958 and another in 1962 respectively.

Sim Woh Kum was born in 1933, as the only child and son of his parents. His father died when he was ten years old, making him being raised by his mother. Sim had little to no education in his childhood, and he had to help his mother Yip Kum Koi to do manual labour. He became an apprentice of a mechanic at age 16, but he lost his job four years later. Sim then became a HDB sweeper and also worked part-time as a school canteen stallholder.