Had you told your current employers that you would be leaving? Are the two jobs in the same city? If not, I highly doubt that you'll have any problems.

I've heard again and again that contracts aren't worth me paper they're written on, in this case that may work in your favour!

Breach of contract? Not good.

Isen't there a 'trial period'? (ie both parties have the right to cancel the contract in the first 30-90 days)

it is not a good practice but you can cancel the contract as long as they did not start any paper work for you fec. so do it quickly. 

The contract will not legally begin until they have provided you with the correct visa paperwork 

Just give me the work.. haha..
I think actually that in the contract there should be a part telling you which options you have for quitting or cancelling. I am sure that this must have been included the contract.

At worst, if the above doesn't work, try explaining this 'need'. If it is genuiinely a need, and you have extremely limited options, then perhaps they will fully understand and let it go.

Remember, though, that you're definition of 'need' may not be someone elses!

There should be a clause in the contract that deals with the cancelation of a signed contract and this will also attract a fee to the company and the amount will also be stated

usually near the end of the contract on the last page 

I'm not a lawyer but I've seen plenty of contracts 

talk to somebody in human resources position and show them the contract.

 good luck and let us know what happens

First consider the enforcability of the contract, and then if it is enforcable, what are the chances that your employer will come after you and sue you, and the amount of penalty at stake. 

Remember that jobs are so easy to lose anyway after you get them, that if you really are afraid of a penalty, you can actually start the job, and then be immediately found "unsuitable" for the position (not hard to do, obviously).  But this is not advisable, because your employer might decide to withhold a "release letter" from you which will keep you indefinitely unable to obtain another work visa, and will most likely be done just for the sheer ego-trip they get out of being able to exercise that kind of control over some poor schmuck's future livelihood.

But generally speaking, just dash.  They might be mad, but they probably won't take action.   You might not be as important to them as you're afraid of.  Besides, was there anything in the contract that benefitted you?  Any amount of money that has started moving already, because the employer is so eagerly anticipating your arrival?  If not, it's hard to say how the employer has been damaged.  In theory, if there was a "shortfall of hours" clause, you were agreeing to be bound to that employer for potentially 0 income per month (no guarantees or benefits at all).  Any good judge should be able to look at that contract and determine that it neither benefitted you nor damaged your employer (also the fact that the Chinese government does not recognize employment as having legally  begun if the contract is not yet bound to the appropriate visa), and promptly throw your employer's case out of the court.

I think you guys are missing his point, he didn't leave his current position and he signed a contract that the job did not start. Legally, you must begin the job and the company provide the paper work for the visa and it must be complete before a contract legally begins. This is why L visa workers always get screwed

Go to the airport....

according to law, employee should have the right to choose a job based on his will, even concluded a labor contract, the employee is eligible to terminate the contract,  but he should give a notification to the employer one month in advance.

we might exchange more.

Liu :13793238107