When you call a song "my sippalbeon" at a karaoke room, that number carries the history of Japanese classical theater! Around the 17th century, the Ichikawa Danjuro family, an illustrious line of kabuki actors, selected and codified eighteen short pieces that had been wildly successful across the generations. People called this collection the "Kabuki Juhachiban" (十八番), literally "the eighteen numbers." So sippalbeon originally meant "the eighteen signature pieces a single house performs best." When the term entered Korean during the colonial period, it settled into the sense of "the thing you are most confident in, your favorite song." Because it is a trace of Japanese, the National Institute of Korean Language recommends replacing it with dangol norae ("go-to song") or dangol janggi ("go-to specialty"). Interestingly, the same characters are also read ohako (おはこ) in Japanese — a reading some trace to the practice of storing a master's secret techniques in a box.