Whether because they are bored, driven to absorb as much of life's wonder as they can, or because they regard certificates as legups on the career pole, many Japanese of all ages are flocking to fonts of knowledge on everything from kanji (Chinese written characters), to shochu (low-class distilled spirits) to movies and aromatherapy.
In particular, the popularity of tests on history, culture, food, local industries and locally famous people has been skyrocketing since the launch of the "Tokyo City Guide Kentei (Tokyo City Guide Test)" in November 2003.
After that -- almost before you could name all 29 stations on the capital's Yamanote loop line -- eager learners could avail themselves of the "Hokkaido Kanko Master Kentei (Hokkaido Sightseeing Master Test)" and the rather odd-sounding "Takasakiyama Saru Hakase Kentei (Mount Takasaki Monkey Doctor Test)" in Oita Prefecture or the "Akashi Tako Kentei (Akashi Octopus Test)" in Hyogo Prefecture, to name but a few.