Though I concur with M/S KK!HR and Nathrao on their explanatory note about the unconventioal condition imposed by the particular Management for the purpose of retaining talented employees in the organisation, I would emphasize that such a condition smacks of indirect bonded labor system. This condition also implies that no resignation would be accepted within the stipulated period. Suppose, an employee finds a better opportunity within a year or two and submits his resignation, most probably it would not be accepted but only rejected in order to avoid documentation of a formal relief. Naturally, the employee would be tempted to walk out without a formal relieving orders as well as experience certificate deeming the explicit condition in the offer letter already issued as a proof of his tenure in the Company. Then, the Management can play the game of employment abscondment and torture the employee or spoil the back ground verification with a wanton claim of continuation of his services on record. Therefore, I would suggest that if the questioner is optimistic about his employability and shrewd enough, he can negotiate with the Management to substitute the condition with sufficiently long notice period, if any as they deem reasonable.