In 1995, sales of pagers were booming among Japan’s teenagers, and NTT Docomo’s decision to add the heart symbol to its Pocket Bell devices let high school kids across the country inject a new level of sentiment (and cuteness) into the millions of messages they were keying into telephones every day. Docomo was thriving, with a bona fide must-have gadget on its hands and market share in the neighborhood of 40 percent. But when new versions of the Pocket Bell abandoned the heart symbol in favor of more business-friendly features like kanji and Latin alphabet support, the teenagers that made up Docomo’s core customer base had no problem leaving for upstart competitor Tokyo Telemessage. By the time Docomo realized it had misjudged the demand for business-focused pagers, it was badly in need of a new killer app. What it came up with was emoji.