Dragon tiles: Red Dragon, Green Dragon, and White Dragon. The term dragon tile is a Western convention introduced by Joseph Park Babcock in his 1920 book introducing mahjong to America. Originally, these tiles are said to have something to do with the Chinese Imperial Examination. The red tile ("中"榜, zhōngbǎng) means passing the examination to clear the way to officialdom. The green tile ("發"財, fācái, literally "get rich") means wealth. The white tile (白板, báibǎn, literally "clean slate") means freedom from corruption. It usually has a blue border to distinguish from replacement tiles and prevent alterations. In the original Chinese mahjong, these pieces are called jiàn (箭), which represents archery, and the red "中" represents a hit on the target. In ancient Chinese archery, one would put a red "中" to signify that the target was hit. White "白" represents failure, and green "發" means that one will release the draw.[citation needed]