Ko-gu-ryŭ soon heard the ominous news and she took it as a presage of evil for herself. She immediately threw a powerful army across the Sil-la border and stormed the Ch’il-jung Fortress. The records naively remark that they filled the commander as full of arrows as a hedgehog is of quills.
Now that Păk-je had been overcome China took up with alacrity the plan of subduing Ko-gu-ryŭ. The great final struggle began, that was destined to close the career of the proudest, hardiest and bravest kingdom that the peninsula of Korea ever saw. The Păk-je king who had been carried to China died there in 661. In that same year Generals Kye-p’il, So Chŏng-bang and Ha Ryŭk, who had already received their orders to march on Ko-gu-ryŭ, rendezvoused with their forces at Ha-nam and the warriors of the Whe-bol together with many volunteers from other tribes joined the imperial standards. The plan was to proceed by land and sea. The Emperor desired to accompany the expedition, but the death of the empress made it impossible.
Meanwhile matters in Păk-je were becoming complicated again. A man named Pok Sin revolted against the government, proclaimed Pu-yŭ P‘ung, the son of a former king, monarch of the realm and planned a reëstablishment of the kingdom. This was pleasing to many of the people. So popular was the movement that the Emperor feared it would be successful. He therefore sent a summons to Sil-la to send troops and put it down. Operations began at once. Gen. Yu In-gwe besieged Ung-jin the stronghold of the pretender and chased him out, but a remnant of his forces intrenched themselves and made a good fight. They were however routed by the combined Sil-la and Chinese forces. But in spite of this defeat the cause was so popular that the country was honeycombed with bands of its sympathisers who gained many lesser victories over the government troops and their Sil-la allies. The Sil-la general, Kim Yu-sin, was very active, passing rapidly from one part of the country to another, now driving back to the mountains some band of Păk-je rebels and now holding in check some marauding band from Ko-gu-ryŭ. He was always found where he was most needed and was never at a loss for expedients. It is said that at this time rice was so plentiful in Sil-la that it took thirty bags of it to buy a single bolt of grass cloth.