Sticky rice mortar was invented in ancient China utilizing organic materials in inorganic mortar. Hydraulic mortar was not available in ancient China, possibly due to a lack of volcanic ash. Around 500 CE, sticky rice soup was mixed with slaked lime to make an inorganic−organic composite mortar that had more strength and water resistance than lime mortar. Sticky rice played a major role in maintaining the durability of the Great Wall as well as tombs, pagodas, and city walls. Sticky rice mortar had high adhesive strength, sturdiness, waterproofing capability, and prevented weeds from growing as crude mortar made of sticky rice and burnt lime created a seal between bricks that would rival modern cement in strength. During the Ming dynasty (1368–1644 AD), brick-making techniques improved sig