The grapheme structure of Chinese characters is a hierarchy of three levels: characters, components and strokes. Among them, characters are at the highest level, components at the middle and strokes at the lowest level.
According to the locality of different components, Chinese characters have 14 types of structures: left and right, such as 
, 
and 
; upper and below, such as 
, 
, 
and 
; left, middle and right, such as 
, 
, 
and 
; upper, middle and below, such as 
, 
, 
and 
; right upper enveloping the rest, such as 
, 
, 
and 
; left upper enveloping the rest, such as 
,
, 
and 
; left lower enveloping the rest, such as 
, 
, 
and 
; right lower enveloping the rest, such as 
; enveloped on the upper three sides, such as 
, 
, 
and 
; enveloped on the lower three sides, such as 击, 凶, 函 and 画; enveloped on the left three sides, such as 区, 巨 and 匣; enveloped on all sides, such as 
, 
, 
and 
; single-element structure, such as 
, 
, 
and 
; special structure, such as 
, 
, 
and 
.
All components of Chinese characters fall into the above categories of grapheme structures.
（Source: chinaculture.org）
