The phrase comes from Portuguese-speaking mahjong circles, where riichi is the Japanese term for declaring a ready hand that can win on the next drawn or discarded tile. Saying someone does not have riichi is a way to deny them that advantage and point out a missed opportunity. The clip has circulated as a reaction sound among players and streamers who share mahjong moments online, especially when a hand falls apart or a rival overplays their position. Its appeal lies in that insider knowledge, which makes the taunt land harder for people who know the game.