In 1921, the section of the route between Baba (now Zeze Station) and Kyoto on the Tokaido Main Line was switched to its present form via the Higashiyama Tunnel route and, at the same time, the remaining section between Kyoto and Inari was connected to the new line of the Nara Line from Momoyama Station and was incorporated into it (refer to "Nara Line" for details).
1921年に東海道本線の馬場（現在の膳所駅）-京都間が東山トンネル経由の現在線に切り替えられ、同時に残る京都-稲荷間が桃山駅からの奈良線の新線と接続され同線に編入（詳細は奈良線を参照のこと）。