The erhu, also called nanhu,( "southern fiddle"), and sometimes known in the West as the "Chinese violin"
The erhu can be traced back to instruments introduced into China more than a thousand years ago
and is originated from Central Asia.
The erhu is almost always tuned to the interval of a fifth.
The inside string (nearest to player) is generally tuned to D4 and the outside string to A4. This is the same as the two middle strings of the violin. (source: Wikipedia)