Their official name is TVXQ (Tong Fvang Xin Qui). They're known as THSK (Tohoshinki) in Japan and DBSG (Dong Bang Shin Gi) in South Korea. They're all Korean but they've been working in Japan for a while now and have released Japanese albums and singles. So maybe that's why you're confused.

they're south korean i've their mvs they are amazing dancers and i also like their songs they sing in japanese too you should definitly check them out

HEY! TVXQ is a Korean boy band. They are from South Korea. They are also very popular in Japan. They sing in Japanese also. They are also called DBSK. I love their songs. They are really nice dancers!! (^-^)