Born in
Kutaraja,
Aceh,
Dutch East Indies, his father was Yap Sin Eng and his mother was Hwan Tjing Nio. Yap's family, living in genteel but reduced circumstances, was part of the
Cabang Atas or the local Chinese gentry; through his father, Yap was a great-grandson of Yap A Sin,
Luitenant der Chinezen of Kutaraja from 1901 until 1922, a high-ranking position in the colonial civil bureaucracy. Of
Chinese Indonesian heritage, Yap was an advocate for human rights. He believed achieving minority rights needed to be part of the larger struggle for the rights of all people. Despite his Cabang Atas background, he turned down an offer to join the influential political party
Chung Hwa Hui due to his skepticism of the latter's elitist outlook. ==Career==