Since the start of the Edo Shogunate, the government had not considered it possible that such an attack would occur on the palanquin of a daimyo (a Japanese feudal lord), so the Hikone clan was caught unawares.
江戸幕府が開かれて以来、幕府には江戸市中で大名駕籠を襲うなどという発想そのものがなく、彦根藩側の油断を誘った。