The Khanda was introduced by the 17th century Sikh guru, Hargobind Ji. The circle shape in the upper center of the symbol represents the cauldron in which food was prepared. The vertically-positioned sword that divides the caldron in half was used by the 17th century guru, Gobind Singh.
The two-sided blade has symbolic meaning as well. One side is the Bhagti, representing spiritual power, and the other side is the Shakti, representing a kind of cosmic energy. The two swords wrapping the caldron and double-bladed sword represent the Bhagti and Shakti doctrine of Sikhism.