Formed in 2004, Kotak (Indonesian for “square”) have become a musical phenomenon largely thanks to the prowess of lead singer Tantri, whose towering vocals have carried the female rocker torch since 2006 when she joined the group with bassist Chua. Kotak’s sophomore album, 2008’s Kotak Kedua, helped thrust the Jakarta-based band—and Indonesian rock—to new heights of popularity. With their mood-spanning pop-rock balladry, Kotak continue to prove that it’s hip to be square.