his, her, its

其 is a pictograph of a winnowing basket. A winnowing basket is a tool used to separate the chaff from grain by tossing it into the air; after the impurities are blown away, the useful grain remains. Therefore, 其 carries the sense of something specific, and is used as a third-person pronoun or as a reference to things. In addition, winnowing baskets are mostly woven from bamboo strips, so the character 箕 was later created to take the place of the original meaning of 其.