I've seen people say that you don't need a Chinese partner, I've done business in China, I needed a partner company, and I was only doing software.
You need to share your IP with your Chinese Partner company. Your Chinese partner company is partially owned by the Chinese Government. When you share your IP with your Chinese partner company they share it with their owner, the Chinese Government. The Chinese Government then shares your IP with all the other Chinese companies that could benefit.
The Chinese haven't needed to steal Commercial IP because western companies have been handing it over to them willingly.
Making fakes
I got to know people at my Chinese partner company, and a relative of one guy was in the business of helping western companies manufacture in China. I was lucky enough to get a tour of a few "high end brand" factories. The relative was quite open about the fact that they right down the road was another factory, which I also toured, that looked almost identical to the first, where they were making similar products, almost identical to the first. The only difference was the leather, and quality of the fabric, and the hardware, you can't make a knock-off handbag if you use the same quality materials. The relative did allude to the fact that the cost of the second factory was buried in the cost of the first.
Never China.