There is an excellent Japanese URL shortening service at 縮.jp This service uses Japanese Kanji characters instead of ASCII characters to form the shortened address. There are far more Kanji characters than ASCII characters and so one can produce shorter addresses.
The site refers to the 1981 Jouyou Kanji 常用漢字 which contains 1945 characters. Thus with just two Kanji characters there are 3783025 unique combinations. With three Kanji characters there are 7357983625 unique combinations.
The 2010 Jouyou Kanji has 2136 characters and so would generate many more shortened addresses for a given number of characters used in the shortened form. I am, though, assuming that this service is using the 1981 Jouyou Kanji character set.
The shortened addresses are ideal for use with Twitter because of current Twitter system deficiencies. ㊀ 地図.縮.jp and ㊁ ta.gd/ラフバラー both resolve to a Google Japanese map of Loughborough. ㊀ works with Twitter but ㊁ does not because the pathname part of the address contains non ASCII characters.
Here are some of my shortened URLs where I have let this service choose the Kanji characters. My observations lead me to deduce that the Kanji are being allocated in Dictionary order ie by radical and then by number of strokes.
Here are some customised shortened URLs where I chose the Kanji characters.