Is japan the only country that has its own map as a unicode symbol? If so, is there a story behind it? I would bet on compatibility with some regional encoding that had it to begin with.
Emoji was basically created to add graphics to Japanese mobile websites in the late nineties when people paid by the byte.
Back then the supplier of the websites also made the phones, and you could only access specific mobile webs depending on your carrier.
The original emoji were mostly create to facilitate online shopping for train tickets for vacation and ringtones. So a lot of these represent travel, food and landmarks.
Edit: this is for Japanese handsets and carriers. That was pretty unclear before the edit
The original set of emoji was created by one Japanese person in a weekend for a Japanese mobile operator. So these images, like the blood types, the astrology signs and the cats and later the rice ball and the pile of poo are images Japanese people would want to use in their communication.
The Wikipedia page of the creator has some links to the origin story:
Back then the supplier of the websites also made the phones, and you could only access specific mobile webs depending on your carrier.
The original emoji were mostly create to facilitate online shopping for train tickets for vacation and ringtones. So a lot of these represent travel, food and landmarks.
Edit: this is for Japanese handsets and carriers. That was pretty unclear before the edit