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.
In Okinawa, people from the mainland are sometimes called Yamatonchu.
Katakana spelling is common for this Ryukyuan dialect word; usually written in kana.
Kanji spelling exists but is rarely used; the word is normally written in kana.
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).