Given the close proximity and long history of interaction of various kinds within East Asia, the great influence of Chinese in both Japanese and Korean, and the similar structures of Japanese and Korean, are there any old words known to have come into Japanese from Korean, and if so, are there any which are written in kanji?
We know that modern Korean loanwords are written in katakana such as "キムチ" (kimuchi) from "김치" (kimchi) and "ビビンバ" (bibinba) from "비빔밥" (bibimbap), but surely there must be some words taken much longer ago - what are some of them and how are they written?