Surname 怀森 (怀森 
, Wisan 
, Huaisen 
) , in all the world, is quite a rare family name. The surname 怀森 is characteristic of South-eastern Asia, particularly Indonesia, where it is a rare surname, Thailand, and Philippines, where it is a very rare surname. In absolute terms, it is the most numerous in Indonesia, China, and Thailand. Likewise, 怀森 is the forename as well as the last name.