The first set of 176 12×12 pixel emoji was created as part of i-mode's messaging features to help facilitate electronic communication, and to serve as a distinguishing feature from other services.
The additions, originally requested by Google (Kat Momoi, Mark Davis, and Markus Scherer wrote the first draft for consideration by the Unicode Technical Committee in August 2007) and Apple Inc.
"Regional Indicator Symbols" were defined as part of this set of characters as an alternative to encoding separate characters for national flags.
The popularity of emoji has caused pressure from vendors and international markets to add additional designs into the Unicode standard to meet the demands of different cultures.
When transmitted, emoji symbols are specified as a two-byte sequence, in the private-use range E63E through E757 in the Unicode character space, or F89F through F9FC for Shift JIS.
The basic specification has 1706 symbols, with 76 more added in phones that support C-HTML 4.0.