Chindōgu

Chindōgu (珍道具^?) is the Japanese art of inventing ingenious everyday gadgets that, on the face of it, seem like an ideal solution to a particular problem. However, chindōgu has a distinctive feature: anyone actually attempting to use one of these inventions would find that it causes so many new problems, or such significant social embarrassment, that effectively it has no utility whatsoever. Thus, chindōgu are sometimes described as "unuseless" – that is, they cannot be regarded as 'useless' in an absolute sense, since they do actually solve a problem; however, in practical terms, they cannot positively be called "useful."

The term was coined by Kenji Kawakami, a Japanese investor and editor of the magazine "Mail Order Life." 

English language book: 101 Unuseless Japanese Inventions: The Art of Chindōgu, first edition 1995.