noun
Japanese mainlander
Ryukyuan dialect word used in Okinawa and surrounding islands to refer to people from mainland Japan. Often carries a slightly informal or insider tone.
沖縄では、本土から来た人をヤマトンチュと呼ぶことがある。
In Okinawa, people from the mainland are sometimes called Yamatonchu.
内地人 is a more formal, standard Japanese term for a mainland Japanese person, while ヤマトンチュ is a Ryukyuan dialect word with a local, informal flavor.
From Ryukyuan languages, combining 大和 (Yamato, an old name for Japan) with んちゅ (person), a Ryukyuan cognate of standard Japanese 人 (ひと).