"If you do not like [your work]every minute is torture," he added.
He also noted that any prospective employees looking to work at Alibaba, one of the world's biggest tech companies, should be prepared to work long hours if they want to succeed.
"Or why bother joining? We do not lack those who work eight hours comfortably, "Ma wrote.
Other China's tech entrepreneurs agree with the policy too. Richard Liu, founder of Alibaba rival JD.com, reportedly laid off 'slackers' in his company who were not putting in the hours.
In a statement to Reuters, JD.com said it "is a competitive workplace that rewards initiative and hard work, which is consistent with our entrepreneurial roots. "
" We're getting back to those roots as we seek, develop and reward staff who share the same hunger and values, "JD.com said.
Still, many Chinese users criticized the policy on social media, citing that a 996 schedule would interfere with their home life.
However, billionaire Richard Branson disagrees with long work weeks.
In a blog post last December, the Virgin Group founder wrote that while he believes the idea of working 9 to 5, five days a week, with the weekends off will be a thing of the past due to the rise of technology, he believes it's good news for workers.
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"As Google's Larry Page and others have said, the amount of jobs available for people is going to decrease as technology progresses, "Branson wrote, citing innovations such as driverless cars, advanced drones and even pilotless planes as examples.
" On the face of it, this sounds like bad news for people. However, if governments and businesses are clever, the advance of technology could actually be really positive for people all over the world, "he added.