Gacha

The name comes from street-corner capsule toy machines — the "gasha" of turning the lever and the "pon" of the capsule dropping out. That sound became the informal name for the mechanic itself (Gashapon is a registered trademark of Bandai). One early online application was the "Gashapon System" added to the Japanese version of MapleStory in 2004. It became mainstream in mobile social games in the 2010s, and turned into an everyday habit through games like Puzzle & Dragons (2012). Never knowing what will come out with each pull — this format draws most directly from the spring of To Chance that has run since the knucklebones of five thousand years ago (see The Vein of Chance). The chase between the mechanic and the law continues too; I wrote about that in W4's "Gacha and Its Regulation."