After the Nara period and through the Heian Period (794-1192) a flooding inflow somewhat lessened, partly because Japan became more and more its own and looked less at China for guidance in conducting the daily affairs of the governance. But steadily, vocabulary still filtered into Japanese from mainland China. During this periods words such as following were introduced: kandau 勘当 'punishment' (Modern Japanese kandō), kesau 化粧 'make up' (Modern Japanese keshō), henge 変化 'change, metamorphosis' (Modern Japanese henge, henka), kauji 講師 'instructor, speaker' (Modern Japanese kōshi), touso 屠蘇 'sake infused with spices' (Modern Japanese toso), byakusan 白散 'medicinal herbs,' kaizoku 海賊 'pirate', bouza 病者 'sick person' (Modern Japanese reflex would be byōnin 'sick person'), kaushi 格子 'window latticework' (Modern Japanese kōshi), boutan 牡丹 'peony' (Modern Japanese botan), to name a few.
Significantly, around this time, Chinese words began to be more assimilated into the Japanese language. Evidence for this found in fusions of Chinese and Japanese word elements. Examples are numerous (Japanese word elements in bold): akatuki 伽閼杯 'water vase' (aka- 'water' (cf. Sanskrit argha, Latin aqua, English aqua- 'water') + -tsuki 'vase, cup'), gakuya 楽屋 'music hall' (gaku 'music' + -ya 'room'), oihousi 老法師 'old Buddhist monk' (oi- 'old' + houshi 'Buddhist monk'). In the ensuing middle ages of Japan (roughly 1200-1600 A. D.), words from Chinese continued to be borrowed. Here the list includes undon 饂飩 'udon noodles' (Modern Japanese udon), noren 暖簾 'shop curtain, noren,' huton 蒲団 'futon' (now in common use in English), mandiu 饅頭 'bun, steamed bun' (Modern Japanese manjū), yaukan 羊羮 'jellied sweets' (Modern Japanese yōkan). Many of these words were brought back from China by visiting monks or Chinese religious leaders who came to Japan to spread Buddhism.
Borrowing in the 16th Century and Later
Chinese words continued to be brought in during this period. A noteworthy event took place around this time—a second influx of foreign vocabulary of a different kind. This began at the end of the 16th century, when Portuguese and Spanish merchants came to Japan for trade and for spreading Christianity. Along with these merchants a large number of new words came into Japanese from these languages. Words of Iberian origin from this period include kappa 'rain coat' (Portuguese capa 'cape'), karuta 'playing cards' (Portuguese carta 'card'), konpeitō (Portuguese confeito 'sweets'), juban 'undergarment' (Portuguese gibão 'undergarment'), pan 'bread' (Portuguese pão 'bread'), botan 'button' (Portuguese botão 'button'). Spanish contributed relatively few words--meriyasu 'a type of fabric' (Spanish medias 'socks').
Toward the end of the 16th century and at the beginning of the Edo period (1603-1878), Japan intensely persecuted Christianity, shutting out Spanish and Portuguese missionaries, who were the main source of foreign words. Also, from the 17th century on until about 1850, Japan sealed itself from outside during the Edo period, shutting down much of foreign trade, and, as a result, limiting infusion of words from the West. During this period of isolation policy, only the Dutch, Chinese, and Korean were allowed to come and go; international trade was limited to those handled by them. In terms of intellectual intercourse, only China and Dutch studies were sanctioned by the government, a fact that meant that only certain vocabulary having to do with Dutch learning and China studies came into Japan during this time.