Welcome to the forums from the Wiregrass! You have a .38 Military & Police Model 10-6 from 1972. It was likely a police gun in China or Japan. The X-like mark on the right side looks like oriental script to me. I don't know what it means. CAI International was the importer, thus the butt stamp. They usually hid these better than that. Interesting gun!
Update: I did some searching of Chinese characters. The X on your gun is pronounced Yi in Chinese and it means mow, cut or regulate. My guess is means the gun was released for sale by the LE organization that was using it. In this regard, it is much like the British/Canadian broad arrow. Many Chinese characters are used by the Japanese. In Japan, the X would be pronounced "me." I have yet to find a translation but I suspect it means the same thing as the Chinese.