"Hiyah," participants shout as they throw punches under the watchful eyes of instructors.

There are 32 participants in the SHE self-defense class organized by She Will Be Strong organization in partnership with the Ho Chi Minh City Taekwondo Federation from the first week of April at a hotel conference room in District 1.

Ranging in ages from as young as six to 45, 99 percent of the students are female, except for one man who brought his daughter to the class and decided to give some of the techniques a try himself.

The class focuses on introducing self-defense psychology, understanding the human body and weaknesses and boosting self-confidence, according to Than Thuc Quyen, vice president of She Will Be Strong.

Every defense move is tailored to tackle a particular intimidating situation and enable a quick getaway: It could be someone tightly gripping a wrist or arm or approaching from the front to strike a blow.

"Don’t forget to cover your face with the other fist so you protect your face. Use your hip to get more force," martial artists from the federation shout instructions between each rehearsed throw of a fist or elbow while offering the students their palms as punching bags.

Dang The Vinh, 62, vice president of the federation, says: "Women need to know how to defend themselves, especially in case of abuse or violence."

Vinh has a teenage daughter who is aware of what constitutes a dangerous situation and knows how to protect herself, thanks to her father.

Desperate times, desperate measures

A case of child sexual harassment triggered public outrage this month after CCTV footage from an elevator in a Saigon apartment showed a man holding and kissing a little girl.

He was identified as Nguyen Huu Linh, former deputy chief prosecutor of Da Nang, who retired in 2018. He initially told the HCMC police that he had found the girl cute and merely "petted" her.

"It pains me a lot to watch these footage and see kids without the ability to protect themselves being molested by perverts," a reader wrote in to VnExpress.

"The law cannot be lenient and forgive perverts who hurt the body and soul of children."

But Linh’s action was just the tip of the sexual perversion iceberg.

Last December the principal of a high school in the northern province of Phu Tho was found to have sexually assaulted many boys in his school for several years.

Last month another video showed a man forcibly kissing a woman in an elevator in Hanoi, and the public was even more aghast when it was revealed he walked free with a paltry fine of VND200,000, or less than $9.

All these scandals shine a light on the poor legal enforcement in Vietnam when it comes to sexual harassment.

Many people have argued in fact that sexual crimes are on the rise partly because punishments are too lenient.

Out of 1,600 reported cases of child abuse last year, 80 percent involved sexual assault, the Ministry of Public Security said at a conference last Thursday.

Ngan Giang, head of communications at She Will Be Strong, said it has begun the self-defense classes because of the many cases of bodily violation of girls and women, especially the one involving Linh, one who is supposed to have full legal expertise on the issue.

Some people coming to its classes because they were infuriated and outraged by Linh’s action, like Bach Minh Ha, 40, and her daughter Phan Ngoc Ha Anh, 13.

It is not common for children in Vietnam to know what constitutes bodily violation or sexual harassment, let alone how to react when it happens to them, but Anh says confidently she does, thanks to her mother and some events organized at her school.

Ha tells VnExpress International: "I don’t think there is an exact number but I’m certain 80-90 percent of women have been harassed in Vietnamese society. I’m one of them. It doesn’t matter what the action is, whenever somebody touches you without your permission, that’s a violation. And I made sure my daughter knows this."

The yoga teacher plans to tell about this course to her students and also neighbors in her apartment building.

She also plans to make connections to bring the class to schools in the city, including her daughter's.

Not far away another self-defense class takes place in a muay Thai studio in District 3.

The students, aged between five and 10 years, imitate Tran Trung Son, their martial arts master, and look like tiny versions of him. Son is a former coach of the Vietnamese muay Thai national team.

He is a father of two, a daughter, 12, and a son, seven. Appalled by the recent incidents of child harassment, he decided to begin a free three-month self-defense course for children in March.

Son tells his students: "I’m going to teach you how to maintain a safe distance with strangers. If they try to attack you, you use the defense techniques I teach you, okay?"

They agree in unison.

"You are so pretty. Oh let me pet you." Son puts on a harasser’s persona as he teaches each child how to avoid a stranger’s unwelcome touch.

He uses the word "pet" repeatedly on purpose to clearly teach the children it is not an acceptable reason for any stranger to touch them.

Phan Thi Kim Oanh, a mother of two, tells VnExpress International, smiling: "When I tried to kiss my daughter, she used what Son taught her in class and slapped away my hand and pinched me real hard. That was after just one lesson." She has a small bruise on her cheek.

Her daughters both enthusiastically put up their hands whenever Son asks for a volunteer, as she observes from the back of the studio, nodding and smiling with obvious joy and pride.

Oanh says since joining Son’s course her daughters have become less reticent and physically stronger.

The class of 20 has a mix of girls and boys, though there were more of the former.

Boys practice punches with Son. Photo by VnExpress/Thanh Nguyen

Da Quang, a five-year-old boy, doesn’t show a moment of hesitation or bother looking down at his feet to see if they are in the right position when Son tells him to throw a blow at him.

His mother, Dieu Phuong, is one of the founders of the Facebook page "Teach your kids self-defense" (Day con tu ve), which is followed by 2,757 people.

Created for parents earlier this month, the page aims to "protect Vietnamese children." Phuong is also one of the people who is helping Son organize and promote the course.

"I am aghast by what is going on with all these child harassment cases," she says.

The mother of two tells VnExpress International she was among those who signed a petition urging authorities to press charges against Linh. She shows the petition she has put on the Facebook page for other parents to sign off on.

"I want my kids to feel less shy and stronger, and I want them to know what is dangerous and how to protect themselves when they are in a situation where they are exposed to harassment and abuse. But I honestly don’t ever want my kids to be in [such a situation]."

On Sunday HCMC’s District 4 announced to open criminal probe against Linh for child molestation charges.