A library made of wind and earth
In the mountains of Gayasan National Park, four simple wooden halls contain one of the world's most complete Buddhist canons, the Tripitaka Koreana. These 81,258 woodblocks, weighing a total of 280 tons, have survived for nearly eight centuries without warping or decay. Their preservation is not the result of modern technology but of ingenious 15th-century engineering that uses natural airflow and materials to maintain a stable internal climate. The buildings, known as the Janggyeong Panjeon, were constructed in 1488 and are an example of passive climate control.
The design harnesses the natural environment. Located on high ground, the buildings are exposed to consistent wind. The architects designed the window systems to maximize this airflow. Each wall has two rows of windows, but their sizes differ between the north and south faces. On the southern facade, the lower windows are much larger than the upper ones. On the northern facade, this is reversed. This configuration creates a natural convection that circulates air throughout the interior, preventing stagnant, humid pockets from forming.
The floor is another important element. It is not a simple dirt floor but a complex system of layers. Builders packed the ground with charcoal, salt, lime, and sand. During the humid summer months, these layers absorb excess moisture from the air. In the dry winter, they release it, keeping the relative humidity remarkably constant year-round. This system has proven more effective than modern, climate-controlled storage; a 1960s attempt to move the woodblocks to a concrete storehouse was abandoned after they began to show signs of decay.
The Eighty-Thousand Tripitaka
The woodblocks themselves are a monumental achievement of scholarship and craft. Known in Korean as the Palman Daejanggyeong, or "Eighty-thousand Tripitaka," they contain over 52 million Hanja characters with very few errors. The carving began in 1236 during the Goryeo dynasty, as a national effort to invoke Buddha's protection against Mongol invasions, and took 16 years to complete. The original 11th-century set of blocks had been destroyed by the Mongols in 1232.
The preparation of the wood was an exacting process designed for longevity. The blocks were made from birch and cherry wood, chosen from specific trees on the southern islands of Korea. The wood was soaked in seawater for three years, cut, and then boiled in salt water. This saline treatment helped prevent decay and insect infestation. Afterward, the blocks were dried in the shade, exposed to the wind for another three years, before carving could begin. Once the 23 lines of 14 characters were carved on each side, the block was coated with a poisonous lacquer to repel insects and framed with metal to prevent warping. Each block measures about 24 centimeters high by 70 centimeters long and weighs between three and four kilograms.