It appears that just this very moment there is Tokyo idol festival going. as they say: "The worlds biggest idol festival where idol fans from across the globe come together".
Tokyo Idol Festival is the worlds biggest idol festival where idol fans from across the globe come together. In fact, last years festival featured 154 idol groups on stage with over 51,000 fans in attendance. Now in its seventh year, the festival returns again with an even bigger scale and more powerful line-up under the concept TOKYO IDOL FESTIVAL, Open the New Chapter!. Tokyo Idol Festival 2016
It all sounds fun and all. But I always had trouble understanding what "idol" in this Japanese sense is and what differes idols and idol groups from other musicians and performers?