The Vietnamese language includes vocabulary derived from Chinese called "Han-Viet words (từ Hán Việt)", and each Chinese character (Kanji) has a Vietnamese reading, which is referred to as "Han-Viet sounds (âm Hán Việt)". The purpose of this study was to survey phonological similarity between Japanese Kanji-words and its corresponding Vietnamese Han-Viet sounds. Native speakers of Vietnamese who have never studied Japanese participated in the survey, and they were required to rate the phonological similarity between Han-Viet sounds and Japanese Kanji-words presented auditorily on a seven-point scale. The results of the survey were compiled in a list. After the survey, a memory experiment was conducted to verify the results. In the experiment, Vietnamese students learning Japanese as a second language were required to memorize visually-presented Japanese Kanji-words through reading aloud. The phonological similarity obtained from the survey was treated as an independent variable and the recall-test scores were dependent variables. The results showed that high phonological similarity led to better recall. This suggests that the phonological similarity data obtained from the survey is reliable.