Let me narrate. The root is from Mahabharath. Pandavas complete 14 years of agnayatha vasa (exile). On completion the pandavas are in Viraat Rajas kingdom.
Arjuna first does pooja to his weapons, which includes Gandiba. This day is #AyudhaPooja
Next day Arjuna single handedly decimates the kurava army and that day is celebrated as #Vijayadasami.