Panchjana is a navigator; captain of the ship in which Lord Krishna sailed to rescue the son of his Guru Sandipani. After a diplomatic victory over of panchjana, krishna could succeed in his task after a great voyage in the same ship. Krishna learnt Navigation during his diplomatic handling of Panchjana. During this period Panchajana gave him his great Conch, used in navigation. The same was named by Krishna as Panchjanya, which was with the Lord during the entire course of Mahabharata and throughout the Krishna avatara.
References
Panchjana Wikipedia(Text) CC BY-SA