One of the main features of Wubi is the last-stroke grapheme identification codes that distinguish between characters of a similar shape. The identification codes are assigned according to the shape of the last radical of the character. The purpose of identification codes is to help users master the Wubi input method at three different levels.
In level A, for beginning users, all three graphemic types with less than four codes have identification codes.
In level B, for intermediate users, only the left-right shaped Chinese characters have identification codes.
In Level C, for advanced users, identification codes are not used.