The shamisen or samisen (Japanese: 三味線, literally "three taste strings"), also called sangen (literally "three strings") is a three-stringed musical instrument played with a plectrum called a bachi. The pronunciation in Japanese is usually "shamisen" (in western Japan, and often in Edo-period sources "samisen") but sometimes "jamisen" when used as a suffix (e.g. Tsugaru-jamisen).
(Note: this article uses the Hepburn romanization in accordance with Wikipedia policy. Some Japanese web pages, however, use the Kunrei-shiki (ISO 3602) and Nihon-shiki (ISO 3602 Strict) romanizations, according to which shamisen becomes syamisen, jamisen becomes zyamisen, bachi becomes bati, and Tsugaru becomes Tugaru.)