In 1944, Kawilarang's father was presumed killed while he was a POW on the Japanese cargo ship "Junyo Maru" (see his father's Japanese detention card at the Dutch National Archives website). The ship was carrying 3,000 Menadonese, Ambonese, Indo-European, Dutch, British, Australian, American POW's, and over 3,500 Javanese Romusha when it was sunk by the British submarine HMS "Tradewind". Kawilarang recalls being told about the tragedy: "I prayed in silence. I did not cry. The Japanese had given me enough practice in digesting pain and suffering in silence."