Japanese-Chinese; Japan and China
Refers to things that are both Japanese and Chinese, or to the two countries together. Often used in compound terms like 和漢薬 (Japanese and Chinese medicine) or 和漢混交文 (mixed Japanese-Chinese writing).
This dictionary contains Japanese and Chinese words.
Cultural exchange between Japan and China has a long history.
mixed Japanese-Chinese writing style
Compound of 和 (wa, 'Japan') and 漢 (kan, 'China'). The reading わかん is a straightforward combination of the on'yomi of the two characters.