Yes, SAMISENS is a Scrabble word!

Letter values in Scrabble US: S 1, A 1, M 3, I 1, S 1, E 1, N 1, S 1.

Is it a valid word?

SAMISENS is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

a Japanese stringed instrument resembling a banjo with a long neck and three strings and a fretted fingerboard and a rectangular soundbox; played with a plectrum