Back then, Silla sea merchants, including Bogo JANG, prospered in the neighborhoods of the Shandong Peninsula of China and, with the help of Sillans residing in Chishanji, he was able to stay in China (although he remained as an illegal resident, he was able to obtain a travel permit).
当時、中国の山東半島沿岸一帯は張宝高をはじめとする多くの新羅人海商が活躍していたが、山東半島の新羅人の港町・赤山浦の在唐新羅人社会の助けを借りて唐残留に成功（不法在留者でありながら通行許可証を得る等）する。