The Japanese popular culture, or shortly J-pop, includes many cultural components beyond the music industry, such as anime, manga, and video games (all of which often includes music). However, the term J-pop was dominantly used to refer to the modern Japanese music. Whatsoever, the Japanese musical market is the second largest in the whole world [source]. While Japanese music doesn't gain considerable popularity outside Japan (esp. if you compare it to K-pop), it doesn't mean that it is worthless to listen to. Indeed, I love J-pop music (not to mentioned other Japanese pop-culture thingies) and in all styles and shapes; pop, rock, rap, funk, metal, and children's songs. All are fantastic and exotic! Give 'em a try!