What are the advantages of the chinese civ?

I can win with India easily, Japan is no problem either, but as soon as I choose China I lose all the time.

Even the AI gives me trouble when I pick them.

It's like my armies are made out of paper and are fighting with pillows. Is there a tech that I miss?

Does China play different to the other civs?

I always pick russia as my ally because they provide me with a fort and a factory, is that a mistake?