The victim did not retaliate. After slapping her, Zhao went on to sort her son's toys while saying: "I will do it until you are really, really scared."
The victim subsequently teared and cried quietly when she was alone.
In the morning, Zhao slapped the victim 10 times again as punishment for forgetting to wash some laundry.
A more sustained assault took place later that day, at about 4.30pm. The victim was cleaning the living room when Zhao suddenly asked her to stop and slapped her.
Zhao scolded the victim for the way she was vacuuming the floor and told her to "use your eyes to see".
Shortly after, Zhao slapped the victim again forcefully. The victim was shocked and spoke to the accused.
Zhao then shouted at the victim: "Do it my way! What you're doing is your way! Everything I teach you, everything cannot remember!"
Zhao continued shouting at the victim, who replied again. Zhao got angry and hit the victim's arm and pulled her hair while shouting.
She swung her hand and hit the victim's cheek and arm, and kicked her twice at her upper thigh.
When the victim used her hands to block the blows, Zhao shouted, among other things: "How dare you?!"
Zhao's son was in the living room during this assault and asked his mother why she was hitting the maid, to which she replied that the victim "did wrong" and "hit mum".
When Zhao stopped hitting her, the victim continued with housework while Zhao shouted various things, including: "If you do it your way, I slap you. I will make sure you remember that, and my slap is always harder."
About half an hour later, still unhappy with how the victim had done housework earlier, Zhao walked up to the victim and slapped her forcefully again.
The victim did not retaliate. For the next 15 minutes, Zhao continued scolding her about various issues.
She pulled the victim's hands, kicked the victim at her upper thigh and hit her arm repeatedly while scolding the woman for "arguing" with her.
At about 5.15pm, the victim called the police. She had not reported the assaults earlier as she was afraid of losing her job and feared Zhao, the court heard.
While the victim was making the police report, Zhao stared at her. When the call ended, Zhao immediately slapped the victim forcefully, hit her head, pulled her hair and kicked her while shouting.
When police arrived, they asked to view the CCTV footage but Zhao refused to show it to them.
Zhao's husband returned home later and informed the police officers that there were memory cards in the CCTV cameras. These were seized for investigations.
The victim was taken to the hospital, where she was found to have a contusion on her forehead and abrasions on various parts of her body.
Zhao also suffered bruises from the victim's efforts to defend herself against the assaults.
"HUMILIATING" ABUSE, SAYS PROSECUTION
The prosecution sought at least five to seven months' jail and a fine of about S$1,000, highlighting the victim's vulnerability as a migrant without a support network and in a subordinate position to her employer.
Ms Teo argued that the sustained abuse caused increasing psychological harm with each escalating incident, adding that the victim would cry and feel traumatised when she recounted what happened.
The nature of the abuse was also "humiliating", as it was calculated to bully the victim into submission, said the prosecutor.
Defence lawyer John Koh raised Zhao's post-natal depression in mitigation, although Ms Teo argued that this was found not to have a significant contributory link to Zhao's offences.
Zhao earlier made voluntary compensation of S$6,300 to the victim for the pain and suffering she experienced, her prospective earnings during unemployment and the damage to her phone.
The punishment for voluntarily causing hurt is jail for up to two years, a fine of up to S$5,000 or both. Zhao was liable for an enhanced penalty of one-and-a-half times the maximum punishment as she committed the offences against a domestic worker.
The offence of mischief is punishable with jail for up to one year, a fine or both.