unless the Chinese possessed fused exploding rounds in the Ming period, that "trench mortar" is more likely the Chinese version of a similar European weapon that was used as the light machinegun of its day. OK, the English term machinegun doesn't fit, so it helps to think of the mitrailleur, i.e., a weapon that puts out a lot of shrapnel (mitraille). Of course, fireworks prove that the Chinese had the technology, but I'm not sure they used it in metal rounds.
Also, the Koreans also used a rocket arrow volley weapon during the Imjin wars.
Edited by lirelou - 19-May-2012 at 00:27