[brudgers]

Pushing has far less control because the center of mass is ahead of the applied force and any eccentricity in the applied force causes rotation in a direction other than that in which the force is applied.

On the other hand, pulling a cart means that the cart will rotate toward the direction of the applied force and follow it. The direction of a pulled cart tends to be self correcting (all things being equal).

[anthonyb]

It's also easier to get it over bumps, since you're pulling upwards, rather than pushing down into the ground. I'm not 100% sure that applies so strongly to the chinese design though.