There is also a block with more of these characters in the Supplementary Multilingual Plane named Enclosed Alphanumeric Supplement (U+1F100–U+1F1FF), as of Unicode 6.0.
[3] The parenthesized forms are historically based on typewriter approximations of the circled versions.
[3] Although these roles have been supplanted by styles and other markup in "rich text" contexts, the characters are included in the Unicode standard "for interoperability with the legacy East Asian character sets and for the occasional text context where such symbols otherwise occur.
[3] A circled s (Ⓢ) was used in documents circa 1900 printed by German missionaries, especially the Basel Mission, in the Malayalam language to denote a ditto mark.
[7] The following Unicode-related documents record the purpose and process of defining specific characters in the Enclosed Alphanumerics block: