Apparently, it was to get away from Yamato Province where the nobles and Buddhists who supported the Emperor Tenmu government had gathered, and to build the capital for the new Emperor Tenchi.
が、これは天武天皇系の政権を支えてきた貴族や寺院の勢力が集まる大和国から脱して、新たな天智天皇系の都を造る意図があったといわれる。