Unlike larger [K-pop] groups with official Japanese fan clubs, Shin-Okubo idol groups usually operate on a point card system. Attending each concert usually equals one point (though there are double point days), and purchasing certain merchandise (such as towels or penlights/fanlights) earns extra points. Bringing along a friend for their first concert also earns an extra point, which cultivates fan labor. As the points accumulate various benefits are awarded, often culminating with a rare option like the 5 minute date [with an idol] (say, after 50 points).
Part of a longer series about K-pop fandom that’s very much worth checking out.