King Zhou of Shang, the last ruler of the Shang dynasty, was a tyrant of unparalleled cruelty. He indulged in wine and women, spending his days in debauchery and neglecting state affairs. He trusted slanderers and corrupt officials, persecuting loyal ministers and slaughtering the innocent. He levied heavy taxes and forced the people to build lavish palaces and gardens. He devised brutal tortures, such as the "burning pillar"—a method of roasting victims alive—and took pleasure in watching their agonizing struggles. Under his dark reign, the people groaned under oppression, their suffering beyond words.
Although the Shang dynasty's territory stretched from the eastern seas to the desolate western deserts, from Jiaozhi in the south to remote Youzhou in the north, with garrisons from Cong Pass to Pu River and hundreds of thousands of soldiers, when battle came, the troops refused to die for King Zhou. They shot their arrows backward—arrowheads facing themselves—and cast aside their weapons. With morale so low, the Shang regime teetered on the brink of collapse.
Thus, when King Wu of Zhou, brandishing a golden battle-axe in his left hand and a white yak-tail banner in his right, charged forward in his war chariot with unstoppable force, every place he reached crumbled before him—the army of King Zhou of Shang collapsed and his regime fell apart like shattered tiles and crumbling earth, swift and beyond all rescue.
Later, the idiom "crumbling like tiles" came to be used to describe a complete collapse or defeat.
Source: *Huainanzi*, Chapter "Tai Zu Xun"
Meaning of the Idiom: Later, the Chinese idiom "土崩瓦解" came to describe a complete collapse or defeat.