In general, characters on ancient Chinese bronze inscriptions were arranged in vertical columns, written top to bottom, in a fashion thought to have been influenced by bamboo books, which are believed to have been the main medium for writing in the Shang and Zhou dynasties.

[4][5] The very narrow, vertical bamboo slats of these books were not suitable for writing wide characters, and so a number of graphs were rotated 90 degrees; this style then carried over to the Shang and Zhou oracle bones and bronzes.

[clarification needed] As in the oracle bone script, characters could be written facing left or right, turned 90 degrees, and sometimes even flipped vertically, generally with no change in meaning.

[6] For instance, and both represent the modern character xū 戌 (the 11th Earthly Branch), while and are both hóu 侯 "marquis".

This was true of normal as well as extra complex identificational graphs, such as the hǔ 虎 "tiger" clan emblem at right, which was turned 90 degrees clockwise on its bronze.

[9] These inscriptions, especially those late period examples identifying a name,[8] are typically executed in a script of highly pictographic flavor, which preserves the formal, complex Shang writing as would have primarily been written on bamboo or wood books,[10][d] as opposed to the concurrent simplified, linearized and more rectilinear form of writing as seen on the oracle bones.

[10] The soft clay of the piece-molds used to produce the Shang to early Zhou bronzes was suitable for preserving most of the complexity of the brush-written characters on such books and other media, whereas the hard, bony surface of the oracle bones was difficult to engrave, spurring significant simplification and conversion to rectilinearity.

Furthermore, some of the characters on the Shang bronzes may have been more complex than normal due to particularly conservative[12] usage in this ritual medium, or when recording identificational inscriptions (clan or personal names); some scholars instead attribute this to purely decorative considerations.

Western Zhou dynasty characters (as exemplified by bronze inscriptions of that time) basically continue from the Shang writing system; that is, early W. Zhou forms resemble Shang bronze forms (both such as clan names,[e] and typical writing), without any clear or sudden distinction.

During the Western Zhou, many graphs begin to show signs of simplification and linearization (the changing of rounded elements into squared ones, solid elements into short line segments, and thick, variable-width lines into thin ones of uniform width), with the result being a decrease in pictographic quality, as depicted in the chart below.

In the same areas, in the late Spring and Autumn to early Warring States, scripts which embellished basic structures with decorative forms such as birds or worms also appeared.

Beginning at this time, such inscriptions were typically engraved onto the already cast bronzes, rather than being written into the wet clay of piece-molds as had been the earlier practice.

The traditional forms in Qin evolved slowly during the Eastern Zhou, gradually becoming what is now called (small) seal script during that period, without any clear dividing line (it is not the case, as is commonly believed, that small seal script was a sudden invention by Li Si in the Qin dynasty[29]).

[26] These eastern scripts, which also varied somewhat by state or region, were later misunderstood by Xu Shen, author of the Han dynasty etymological dictionary Shuowen Jiezi, who thought they predated the Warring States Qin forms, and thus labeled them gǔwén (古文), or "ancient script".

It has been anticipated that bronze script will some day be encoded in Unicode, very likely in Plane 3 (the Tertiary Ideographic Plane, or TIP); however, no codepoints have yet been allocated or officially proposed for it (unlike the seal and oracle bone scripts, which both have ranges of codepoints tentatively blocked out within the TIP).