Mongol siege of Kaifeng
... that during the Mongol siege of Kaifeng, the Jin Dynasty used extensive gunpowder technology, including trebuchet bombs and fire lances?
... that during the <b id="mwATc"><a href="./Mongol_siege_of_Kaifeng" id="mwATg" rel="mw:WikiLink" title="Mongol siege of Kaifeng">Mongol siege of Kaifeng</a></b>, the <a class="mw-redirect" href="./Jin_Dynasty_(1115–1234)" id="mwATk" rel="mw:WikiLink" title="Jin Dynasty (1115–1234)">Jin Dynasty</a> <i id="mwATo">(Jin envoys pictured)</i> used extensive gunpowder technology, including <a href="./Trebuchet" id="mwATs" rel="mw:WikiLink" title="Trebuchet">trebuchet</a> bombs and <a href="./Fire_lance" id="mwATw" rel="mw:WikiLink" title="Fire lance">fire lances</a>?