The janggu in matjanggu-reul chida is none other than the janggu, the traditional Korean hourglass drum. In the old days, when farm work grew hard or a feast day came around, people would strike up pungmul percussion music to lift the mood. Barrel drums, janggu, and small gongs wove together into a rolling rhythm. Within it there was a part where two players stood face to face and beat the janggu together — and this was called matjanggu. The prefix mat- ("to face, to meet head-on") was simply joined to janggu. But to play matjanggu properly, the two had to be in perfect time and breath with each other: one strikes, the other instantly catches the beat and carries it on. That give-and-take looked exactly like answering someone's words with an eager "Right, exactly!" And so matjanggu chida came to mean "to chime in and go along with what another person says."