Jaszczuk, who divides his time and work between Warsaw and Japan, told Business Insider that he was living in Tokyo when he began to notice a unique phenomenon.
In the wee hours of the night, he noticed men dressed in business suits fast asleep on the streets of Tokyo.
"The contrast between well-dressed men and the street got my attention," Jaszczuk said.
In 2008, he started photographing the sleeping businessmen that he would come across.
Jaszczuk's photos show some taking to city benches, fences, and subway platforms to get a little shut eye ...
... others are shown simply dozing off standing up.
The more and more he shot, the more common of a phenomenon he said it seemed to be.
Jaszczuk said the slumbering businessmen are easy to find for the most part, if you know where to look for them.
He said he knew that perusing nearby train stations and karaoke bars would always prove fruitful.
"After some research, I knew which areas would be the best, because they are not everywhere," Jaszczuk said.
Tokyo's Shinjuku and Shimbashi districts, in particular, known for their business, commercial, and entertainment centers, were full of dozing employees, he said.
But he would also occasionally find some one-offs elsewhere.
"That's why I was moving all the time," he said.
For more than two years, Jaszczuk said he worked almost every night taking photos of the sleeping workers.
Jaszczuk said he navigated the streets at night by bicycle.
Biking around "did the job perfectly," he said.
"I was hunting," he said.
Although he said he would come across many sleeping businessmen ...
... he said he didn't include photographs of everyone he found in his series.
"I am very picky, I was carefully selecting them among many," Jaszczuk said.
He said that he was looking for style, beauty, and oddity in the slumbering subjects he photographed.
He compiled the images into a book, "High Fashion," that was published in 2018.
Since he was taking photos at night, Jaszczuk said he needed something to light his subjects.
He said he always used a flash, albeit a small one.
Despite the bright flash of light with each shot, he said it didn't bother his subjects.
"They never woke up, ever," Jaszczuk said.
"I'm quick, even when there is plenty of time to shoot," he said.
He said he never had problems of any kind with the sleeping salarymen.
Neither passersby nor the authorities gave him trouble, either.
The photographer said that in his photo work, he usually knows what kind of message he wants to convey before embarking on a project.
But with "High Fashion," it was a bit different.
"The visual part appears first, the message came later," Jaszczuk said.
After just the first few photos were taken, Jaszczuk said he began to explore that message: a cultural phenomenon that had these businessmen sleeping on the streets in between work days.
In fact, Jaszczuk said what he had begun capturing was a symptom of Japan's notorious culture of overwork.
The culture of overwork can be so intense in Japan that businessmen, called "salarymen" in Japanese culture, have even died from overworking themselves.
There's even a name for the phenomenon: karoshi, which translates to "death by overwork."
A 2016 report revealed that more than 20% of people in a survey of 10,000 Japanese workers said they worked at least 80 hours of overtime a month.
The term "inemuri," which translates to "sleeping on duty" or "sleeping while present," describes a cultural phenomenon in Japan that praises napping in public, which implies that an employee has worked him or herself to exhaustion.
Brigitte Steger, a senior lecturer in Japanese studies at Downing College, Cambridge, told The New York Times that inemuri, a thousand-year-old practice in Japan, is more prevalent in white-collar professions.
That's because employees are more likely to be sedentary and can afford to doze off in meetings and the like.
After putting in a long workday, it's also customary for some salarymen in Japan to drink and socialize with their colleagues.
Jaszczuk told Business Insider that it is socially acceptable in Japan to hit the bars after work.
But even more than that, Jazczuk said workers can sometimes feel an obligation to drink with their coworkers and bosses after work hours.
After too many drinks, and having missed the last train that would take them home, some workers are left stranded in the city center.
He said when morning comes, he's never seen them awake from their sleep.
But he's heard that they simply get up and walk back to the office to start the new day.
As for the men themselves, Jaszczuk said they're a product of their work culture.
"These men are the victims of modern life in Japan," Jaszczuk told Business Insider.
He said that they are physically "devastated by the after-effects of working long hours."
"Don't judge them too [hastily,]" Jaszczuk said.
While most of the subjects he photographed were fast asleep...
... even if they were slightly awake, Jaszczuk said he could see how worn out they were.
"When their faces happen to reflect consciousness at all, we see someone completely used, overworked, and exhausted," Jaszczuk said.
The cultural expectation in Japan to devote so much time to work is nothing new.
The karoshi phenomenon, the phrase used to describe overwork-related deaths, dates back to the post-World War II era in the early 1950s.
Determined to rebuild Japan's economy, the then-prime minister Shigeru Yoshida turned to major corporations to incentivize workers into devoting more time to their work.
The plan clearly worked, since Japan's economy is now the third largest in the world.
But an unintended side effect was an ailment spurred by the burdensome levels of stress and exhaustion.
Strokes and heart failure became more common for Japanese employees.
Decades later, karoshi-related deaths are still occurring.
Most recently, a 31-year-old journalist named Miwa Sado died of heart failure in July 2013 after reportedly logging 159 hours of overtime in a one-month period.
Her death was determined to be karoshi in October 2017.
When employees' deaths are classified as karoshi, Japanese corporations are forced to pay a fine.
Sado's employer only had to pay what amounts to $5,000 USD in fines following her death.
The Japanese government has taken some measures to increase a work-life balance in addition to implementing fines on corporations whose employees die of karoshi-related causes.
One of them is a Premium Friday plan launched in 2017 that would give workers the option to leave at 3 p.m. on the last Friday of each month.
But it's seen little success.
Working overtime remains a pervasive aspect of corporate culture in Japan.
Jaszczuk said he wanted his photos to convey that.
"I want to say something when something needs to be said," Jaszczuk said.
He said he felt it necessary to bring attention to how overstressed Japanese workers are regularly.
"The images provoke, irritate, and inform at the same time," Jaszczuk said.