Four Treasures of the Study, Four Jewels of the Study or Four Friends of the Study is an expression used to denote the brush, ink, paper and ink stone used in Chinese and other East Asian calligraphic traditions. The name appears to originate in the time of the Southern and Northern Dynasties (420–589 AD). Four Treasures The Four Treasures is expressed in a four-word couplet: "," (Pe̍h-ōe-jī: bûn-pông sù-pó: pit, ba̍k, chóa, hīⁿ; Pinyin: ) "The four jewels of the study: Brush, Ink, Paper, Inkstone." In the couplet mentioned, each of the Treasures is referred to by a single epithet; however, each of these are usually known by a compound name (i.e. The Brush: , literally "hair brush/pen). The individual treasures have a "treasured" form, each being produced in certain areas of China as a specialty for those scholars who would use them. Brush The brush () is the oldest Four Treasures member, with archaeological evidence dating to Zhou dynasty (1045 BC–256 BC) illustrations on ancient bones. The oldest brush so far dates to Han dynasty (202 BC–220 AD). Brushes are generally made from animal hair, or —in certain situations—the first hair taken from a baby's head (said to bring good luck in the Imperial examinations). Brush handles are commonly constructed from bamboo, but special brushes may have handles of sandalwood, jade, carved bone/ivory, or other precious materials. Modern brushes are primarily white goat hair (羊毫), black rabbit hair (紫毫), yellow weasel hair (黄鼠毫/狼毫), or a combination mix. Ancient brushes, and some of the more valuable ones available on the market may be made with the hair of any number of animals. Each type of hair has a specific ink capacity, giving distinct brush strokes. Different brushes are used for different styles of calligraphy and writing. Brushes are classed as soft (軟毫), mixed (兼毫) or hard (硬毫). Hair is laboriously sorted by softness, hardness, thickness, & length, then bundled for specific uses. The most famous and highly prized brushes are a mix of yellow weasel, goat and rabbit hair, known as Húbǐ (湖筆); highly prized since the Ming dynasty (late 14th century) they are currently made in Shanlian (善琏), a town in the Nanxun District, prefecture-level city of Huzhou, of Zhejiang province (浙江). Ink The Inkstick (, pinyin: ) is an artificial ink developed during the Han dynasty. These first writing inks were based on naturally occurring minerals like graphite