Sejak (), also called dumul-cha (), refers to nokcha (green tea) made of young, tender leaves and buds hand-plucked after gogu ("grain rain", 20âÂÂ21 April) but before ipha ("advent of summer", 5âÂÂ6 May). Also called jakseol () as the tea leaves are plucked when they are about the size of a sparrow's tongue, sejak is best steeped at a temperature of .