The 3 Cardinal Tiles/番子牌（中、发、白）.
There are also 3 Cardinal tiles, also referred to as the three Dragons or Special Honor Pieces. These are Red Dragon, Green Dragon, and White (or Blank) Dragon. The Mahjong set contains 4 of each of these tiles. These are the Honor Tiles.
Red Dragon Tile (means "target down"). Chinese character: 中 /zhōng/
Green Dragon Tile (means "make a fortune"). Chinese character: 发 /fā/
Blank Dragon Tile (means "empty handed" ). Chinese character: 白 /bái/