Gacha

Gacha is the random draw at the centre of most Japanese mobile games. You spend currency, an animation plays, and you receive a character or item chosen by rates you did not set. Rare results are rare on purpose. The pull animation exists to stretch out the second before you find out, which is the part the design is really selling you.

The name copies a sound. Gachapon machines are the capsule toy dispensers standing outside shops all over Japan, named for the gacha of the crank and the pon of the capsule landing in the tray. The mobile version keeps the crank and removes the capsule. Most games now soften the odds with a pity counter that guarantees a rare result after a set number of failures.

Regulation arrived once one variant went too far. Kompu gacha required players to complete a set of random items before receiving a prize, and Japan's Consumer Affairs Agency moved against it in 2012. Publishers dropped the mechanic and began disclosing drop rates. The rest of the model survived intact, and it now funds a large share of the anime tie-ins you see advertised.