Can my employer make me serve 6 months after resignation?

My initial contract that I signed asked me to serve 3 months (which I think may be too much already?) Then my employer came to me in my probation period, scratched out the 3 months and wrote 6 months.

She said the company wants me to serve 6 months if I resign and the company has to give me 6 months in the case of termination.

She signed by where she wrote and then I signed because I was naive and stupid but now I’m questioning if that is even legal? I know it’s downright unethical but I want to know the legal standpoint.

There were some other sketchy things in my contract too. Such as if I resign, I cannot work for a company that “can be seen as a competitor” for a whole year.

I’m a dance teacher so they’re basically asking me not to have a job for a year.

Netizens’ comments

Non compete clauses are typically unenforceable, you can’t stop someone from making a living which effectively they’re doing.For extending your notice period from 3 months to 6, you both signed and notarized it so you’ve agreed to it. The law won’t accept ignorance or naivety or ethics as an excuse.

Contrary to what others have said. Restraint of trade clauses are enforceable in Singapore. However, it needs to reasonable in time, location and scope.What’s reasonable? Depends on your job, seniority.Also, even if it is reasonable, is it beneficial for the company to go after you if you break?If you think the answer is no to any of the question above, you can pretty much ignore itCounter signing on the document is actually quite common for both party to acknowledge the change was agreed. This can be as mundane as you giving a handwritten contract and had to cancel an error.However, it would have been within your right to not sign.Also, even if you sign, it might not be valid. Because there needs to be fresh consideration on your part for the change. If there’s no fresh consideration, the variation pretty much dies. T