Those who committed additional crimes while on the island were confined in mineshafts, a punishment known as "shikinai oikomi," while those who attempted to escape from the island were given a death sentence.
島においてさらに犯罪のあったときは鉱穴に禁錮されたが、これは敷内追込といい、また島から逃亡した者は死罪であった。