After Mao Tse Tung's takeover of China, many of the Yunnanese migrated across the mountains into Thailand, where they and their descendents still live.
Mae Hong Son is one of the lovliest parts of Northern Thailand, with houses that look more Burmese in design than Thai. This has to do with the fact that Mae Hong Son lies on the border with Burma (Myanmar) and the town has many refugees many of whom work as guides. The local people call themselves Tai Yai and insist they are the original Thais, something that is hotly disputed whenever southern Thais come visiting.
If Mae Hong Son offers a glimpse of Burmese architecture, there is another area that offers a Chinese perspective. Set against scenic hills and green velvety mountains, visitors to the Pai area get a rare glimpse of diverse cultures, food and the way of life of Chinese migrants who made the Pai area of MHS their home. The revolution in China was the catalyst for many Yunnan Chinese to make their way into Thailand where they engaged in opium growing until defeated by the notorious drug lord, Khun Sa.
Nowadays the villagers work as farmers or tea growers and the famous Oolong tea can be purchased from the many shops that sell it here. Yunnanese food is spicier than most Chinese food and is a blend of many cultures' cuisine, Yunnan being home to a diverse group of ethnic minorities.
Their colourful costumes, especially the Lisu, a Tibeto-Burman group who wear colourful baggy trousers and the Padaung, the so-called long-necked Karen women, and the colourful festivals they have, are beginning to attract tourists.
It is still relatively new and in the throes of "soft tourism" which means the infrastructure isn't there for overnight stops. You can spend the night in some village houses, but be advised that 5* accommodation is a long way off yet. If you like simple, then this is what you want. But if you like luxury, wait awhile!