I've seen a number of Contax and even a Contaflex TLR camera marked "For China" and believe this mark does not really mean what it plainly says. My opinion is that this marking is a factory code that means, "Not for Sale" and particularly in the valuable American market. All the For China marked cameras I have seen have been characterized by very bad workmanship that includes stripped screw holes filled with a type of hole sealant used by the Zeiss factory to light seal these cameras. It just doesn't make any sense that a camera made in a German factory which is supposedly made for the Chinese market would be engraved "For China" in English. If such a camera was intended for the Chinese market and this was something special, the engraving would have to be in Chinese for it to make any sense. The envidence tells me that this marking was applied to a factory second camera to ensure that it could not possibly find its way into the American market.
In order to understand the importance of the American market to Zeiss we have to touch the circumstances in Germany at the time such cameras were being made. At that time the economic inflation rate was high. Germany was secretly militarizing and so dollars were necessary to buy many of the imported materials required to make the Contax and to allow the fabrication of weapons. At that time the international sellers of strategic resouces knew what Germany was doing and so they insisted on cash payment in dollars for military strategic items like chromium, industrial diamonds and oil. The only way for Zeiss to get the necessary dollars was to sell cameras in the U.S.A. So the American market was a lifeline to Zeiss at the time and it was so precious it had to be protected. Zeiss made absolutely certain that only the highest possible quality goods got sent to the USA to ensure this market would remain undistrubed.