法華經化城喻品說，有導師欲率眾越五百由旬之險難至寶處，恐眾疲倦而還，遂方便於三百由旬之中途作一城，暫為止息。三百由旬者為超三界，譬小乘之有涅槃。文句七曰：「三界果報處為三百。」
The 300 yojanas parable of the Magic City, erected by a leader who feared that his people would become weary and return; i.e. Hīnayāna nirvāṇa, a temporary rest on the way to the real land of precious things, or true nirvāṇa; v. 法華化城品.